the jackson boats thigh pads pack out quickly and because you are playboating more you are pulling on both sides of the boat more often than in river running and your knees might be digging pockets in the thigh braces.
look inside to see and if so i recomend 2 options, the first, and best imo.
wear a knee pad that is tight fitting like a wrestling pad or a support brace like at a drug store. they are both cheap, form fitting and protect your knees if you swim, look for the better least absorbent kind.
option b the more common is to add 1/2 inch thick padding to the thigh braces.
and
you want to be pretty far forward if not all the way when you playboat. the key is to control the boyancy of the bow and slice the stern.
have fun, as trebor once said if you ain't hurtin' you ain't squirtin'
playboating is painful, no shit.