divernva once bubbled...
I found the trim weights to help keep my vertical on the surface.
As for overweighting... the Mares Synchro is strangely bouyant when dry. So to descend, it takes a lot more weight... so much that it's sluggish at depth. To help reduce the weight, I started to kick up on the surface before descending. Basically I bobbed up higher on the surface to create a downward momemtum for the descent. Worked pretty well.
Nice BC overall. Never had problems with mine during the half year I dove it.
Just out of curiosity.. what exactly are the advantages of this BC?