bladders
There is not a stability issue with the h23, use some common sense as to reefing etc . On a wwp forum there was a guy who had been using bricks under his seats for added stability another books . In the event of something untoward happening any added weight on the inside of the boat would not be a good thing . I have read / heard of a system such as you describe in racing boats . To me it is not a good idea ,good luck Mike