Just got back from Labor Day weekend on the Fling. Good time! Here's my additions/comments:
--Take BUG SPRAY for the departure. Mosquitos on the river bank are fierce. Once you're at sea you won't need it, but you'll regret not having it for that one hour or two stretch preceding departure.
--someone else mentioned a camp towel or a chamois instead of a 'beach towel'. Highly seconded. Towels just don't dry easily/well, and take up lots of space on the line. Chamois just get squeezed out and reused, instantly. That's what the captains of the Fling both used
--Mask box or some other small tupperwear to soak your reg. Its one thing to 'stand under the shower' a tad when getting out to rinse off exterior salt, and run water into the mouthpieces, but a good couple minute soak/swish in a filled container, followed by a blow-out with remaining air before disconnecting to let them refill your tank - is a good precaution. We had a couple other people report their regs getting a bit 'sticky' with salt crystals and a bit more per-dive preventative maintenance like this would've prevented it I bet.
--Definitely mark your booties if nothing else. EVERYONE wears black booties. Brand, height, and sole might vary, but you try searching under the bench if someone kicked yours in a random direction while stumbling to their own station post-dive. Maybe ditto for fins...I don't know how many pairs of Quattros I saw.
--alarm clock (or you can use your cellphone if it has that feature). Setting yourself a wake-up for about 5-10 minutes before the boat DMs wake everyone up so you can get to the head and do your necessaries and brush your teeth without having to queue-up in the line can make a big difference in how you start your day.
--some sort of small cushion might not be a bad idea (like a stadium seat) if you can fit it in your bag (use it for extra reg padding?). Those flat 'exhaust pipe' structures on the back are nice and warm and good places to sit on the dive deck...but despite my natural padding my backside felt like hamburger after 3 days of sitting on mostly hard surfaces.
Technique suggestions:
--If you have a fairly small BC so that when wrapped on your tank with integrated weights in, the weights are 'off of' the bench, your tank will NOT stay in the holders when the ship is in side-to-side motion with the waves. So mark your strap height with a small line with a sharpie or something and loosen the strap to drop the BC down so the weights rest on the bench, then just remember to raise and retighten before each dive. Much easier than slotting your weights in and out of the pockets all the time (at least for some of the integrated weight systems), especially on the smaller BCs that this will happen with. I wear a large so my weights weren't suspended and had no problem leaving them in, but my wife's kept yanking the tank over until we removed the weight packs (and she wears less than I) until I figured out it was because they were elevated like this.
--Someone else recommended analyzing your Nitrox fills early. I second this a bit but with a caution: in 2.5 hrs surface interval (minus the time it takes them to get to your tank) there's a lot of time to analyze. But *check your tank temperature* with a hand before doing so (or at least while, and consider your dive plan accordingly). A couple of times my wife and my tanks were really hot (immediately after filling) and we logged them at 3000ish, only to see about 2800 - 2850 the second we hit the water. Of course it never happened to BOTH of us at once, so a couple of dives one of us hit our agreed turnaround pressure much quicker than the other (normally our consumption rates are luckily pretty identical). If we'd known they were measured hot (and there was time for a cool-off) we might've been able to get them to do a top-off.
--REGARDLESS of what they tell you the current and/or vis is like, don't stinge on taking a compass heading as you pick your first direction away from the mooring site (unless you never let it get out of sight). What they say is a 'minor' or 'only moderate' current to those experienced with the FG may not be all that moderate to YOU, and the time between turning around and saying "yeah, I can still see the shadow of the boat and the line" and giving each other the "where the <bleep!> is the boat???" sign is a darn short one. Currents change, the sun goes behind clouds dropping visibility, etc. Treat every dive like your navigation checkout dive during training and you have far less chance of going wrong, and agree on a turn-around pressure ahead of time with contingencies if either of you feel the current is more (or less) than your primary plan assumed. You can always loop around again if you find yourself getting back to the boat viscinity early. (We never rode the "Dinghy of Shame" despite being first-timers, but on the very first dive that was more 'luck' than 'planning'....we scared ourselves back into discipline with that one.
--Use the down-lines for your safety stops (especially if - like me - you like doing a 2 minute stop at 30 prior to the usual 3 at 15-20). Everyone hangs on the mooring line and then the side line - which gets dragged up and down by the mobs).They're weighted strongly enough not to get off-vertical very easily, and there's 4 to choose from (in heavier currents at least 2 on the side of the side line). Don't try for a free ascent unless they allow it in the briefing. If they tell you to use the side line and mooring line for ascents you can do that, and 'hopscotch' over to the downlines once you're close, then back to the side line to continue your way to the back to egress. Only once or twice did I find the currents slack enough that I was comfortable doing a 'swimming safety stop' - traversing freely toward the ladder lines once hitting appropriate depth.
--When you do your giant stride in, give the OK signal and then **get the bleep out of the way!!!**. Either swim straight for the sideline and wait for your buddy there or agree ahead of time which way you're going and go straight into a descent. A lot of people would hang right under the 'drop zone' swishing water to defog their masks, or re-securing octos and guages that slipped out of clips, etc. Remember more than likely you're holding up at least half the other divers if you linger in the way.