why do you think that you would shed weight? you aren't doing anything to change the buoyancy of the rig or you, the tightening of the wing only relates to fixing what is otherwise a horrible wing design. With twin 80's, you need 6lbs of lead to offset the buoyancy of the tanks when they're empty anyway *9lbs of total positive buoyancy, less about 1.5lbs/first stage and another 1lb/side if you're using metal cam bands*, most people need on average 2-4lbs of lead to sink themselves, and the sms100 needs at least 1lb to sink it, so you're doing pretty good in that respect.
Old school bungees are two fold. The webbing spacer helps to keep the bungee from pinching the bladder which keeps air from moving around and is bad, and the loops keep the valves up tighter which serve the sole function of raising the valves so they are inline with your torso. It's aesthetics as well as slightly increasing the efficiency of the rig. Get someone to take a video of you doing flat turns in the pool so you can see both sides and post them here, we might be able to help you make some more adjustments.