Hi Scuba Dog --
I have a couple of thoughts for you...
First, certainly keep up the gym work -- it can only help you to be better fit.
Second, you don't mention whether your open water dives would be from shore or from a boat -- but, from a boat (and even from shore) you might consider splitting the weight. Put some in an integrated bc and some on the weight belt. Then, from a boat, place your inflated and weighted bc in the water. Wear the weight belt. Get in the water (your own bouyancy and that of your exposure suit should help you to manage the weight belt at the surface. Once in the water, put the bc on. When you surface, remove the weight belt and hand it up. Then, depending on the boat, either climb aboard or if necessary, remove the weight pouches and hand them up.
If you would be doing shore dives, you could do something similar by having a buddy help you get your inflated bc into the water while you walk out wearing the weight belt and pushing the floating, inflated bc.. then don the gear -- exit in reverse, or at exit.. remove the weight belt and drag it.
Thirdly, you don't mention your size, but I wonder if the estimate of how much weight you need is accurate. I am 5'7" and wear a woman's size 28 -- I am PLENTY bouyant. With a 3mm suit in salt water, I need about 22 pounds. Now, obviously, you'd be wearing more suit... but still... Often, newbies seem to need more weight than they truly do because they either inhale when trying to initially descend, or they inadvertantly kick when trying to descend. So, I'm wondering if there might be something that could be done to make you more comfortable so you could relax more -- or even a careful observation of your attempts at descending might highlight a small technique change that could make all the difference.
Finally, (of course I have to plug this) is you could join Big Adventures to finish your certification in warm water where exposure suits and weights wouldn't be a problem.
But, in any event, keep working on it!!!
Liz
www.bigadventures.net