What about Kegals? Would that help grip the seat better?
I've never gotten that...intimate...with my seat.
Seriously, use your thighs to grip, and your core muscles to hold up your upper body.
Remind yourself not to straight-arm the bars by periodically flapping your arms like chicken wings (you'll find you can't if your arms are straight and tense).
That solves most cases of wrist strain.
If you still have issues, look at your riding position, grips, and gloves.
