My tandem has a sliding bow seat and a thwart behind it. I'll slide it back traveling down wind (ya like that happens much) but the thwart has never been an issue.

A bag of water in the bow is what I once used for trim when empty. Since I've gone from 130 to 160 a bigger bag was needed paddling empty. I've even had to resort to the bag o water less full when fully loaded under certain conditions.

It's hard to replace a bow paddler with dead weight while keeping a low profile. Rocker might matter some too.

Personally, I don't like paddling at the pivot point but putting weight at both ends isn't the best solution either. It's that centrifugal force and inertia thing. I just want to get from point a to b as quickly and easily as possible. I can't dance. It's just not in my DNA. I could still probably polka though if I had to.   ;D