Got four dives out of six planned in Key Largo, with three deep to the Spiegel Grove and Duane and one shallow reef dive. Some rough conditions out there on the surface this week. Bottom line is I love the S-Tek. Really comfortable in the water and shuffling along the boat. Only real complaint if you want to call it that is my left shoulder strap/pad twisting while putting it on. The monprene would grip the grippy stuff on top of my Henderson wetsuit and want to flip. Not a big deal at all. Spent most of my time figuring out where to put weight. I had two pockets up high on the plate, two on the waistband and two on the cam band. For the most part I had it on the cam band. I'll continue to refine this (and get comfortable with not having much/any easily ditchable weight).Sounds like you've got the right approach and are far more intelligent than most in regards to testing things out in the pool first. I will say that I've had at least 10 more dives since I wrote my short review and I'm loving this kit more and more. I spent last week in Cozumel and the Bahamas with my Cressi Travel BCD and, boy, was I missing the S-Tek.
As far as weighting, I went through the same thing, of course. My situation is a bit more simple, though - I live in Miami and am always diving warm water, AL80s with a 3mm full or shorty. So there's not a lot of variables there. However, I did do some quick calculations and compared the weight of the S-Tek kit to my previous BCD and just figured out the difference between the old and new. That seemed to work for me right off the bat. The only change that I've recently made was to distribute the weight more evenly using the S-Tek trim pockets. 2/2 on the waist, 2/2 in the trim.
Sounds to me that if you're used to diving with 8lbs on the 100s, then you'd maybe increase that to 14lbs on the AL80 (using a 5-6lb rule of thumb). Then since the SP is 6lbs heavier than your old rig, you'd subtract out 6lbs of lead to get you back to 8lbs total. Or something like that
In terms of weight, it was hard to do an accurate weight check at the surface given the waves and cattle boat crowds/urgency to get down. I tried 8 and felt heavy early but good on the safety stop with 700psi left. Tried 6 later and felt better on the dive but floaty on the stop (which was done hanging on a wildly bouncing line anyway). So, more work to do but it's in that 6-8 zone as expected. Biggest revelation for me was apart from the BPW. I lost about 10 pounds of "bioprene" weight last year. I noticed in Cozumel and now Florida that I'm getting chilly in a 3mm at 76-77 degrees F when I did not used to. Getting older and less fat = colder? I dunno.
S-Tek: love the handle and quick drying, loved the trim and buoyancy control of the (or probably any) BPW in general, loved the tank stability. Minor gripe with the shoulder when donning but no big deal. I may try the waist pads on the shoulder at some point. Feeling a little guilty that my first BPW is probably an overpriced Mercedes but it sure is nice.
