Keep shedding lead in 2# increments in each dive until you can't do a safety stop with 500psi in your tank and an empty BC, you'll know when you're under weighted when you can't do the safety stop floating to the surface, then add 2# and you'll be set.
After getting some experience (50 dives or so), try shedding 2# again, and test your boyancy again.
I started with 16#, after some time, I droped to 14#, years later, I droped to 12#, when I got the 6#BP, I droped to 8# ditchable and after 10 or so dives, droped to 6# ditchable.
Right now, I only use 2# ditchable weight and the 8# of the BP+STA brings me to 10# for a net drop of 2# from my original 12#.
I'll be picking up tomorrow from UPS my new wetsuit from scubatoys, so probably I'll have to add a couple of pounds and dial in my weight again.
As you can see, weight has to be monitored once in a while and if you can drop a # or 2, then do it.
