I rebuilt wings similar to your situation! Reading wittman articles, talking to everyone on here, the consensus about flat bottom wing tailwind/cougars and triangular w10 wing tips, is the flat bottom wings seen beneficial improvement on lower stall and lower touchdown speeds, how much I'm not sure. Im building them currently on mine,? so more worth than none.. Now cougar wings are flat but the spar spacing is greater than tailwind, making the wing less than desirable for adding flaps and 24 ft wings, but if you rebuild to your plane and keep the overall wingspan to 23 ft or less, the cougar wing also shows improvement w wing tips. Your also looking at cable actuated alierons if a true cougar while tailwind is push pull, but no observed data that iv found saying this is less than stellar regarding flutter, unless you plan on having a super fast cougar. FYI, those original w8 and cougars were designed w c85 in mind while offering fast cruise, plans stating 170ish knot cruise, but u must keep it light. Guys add on or correct me. I learned from you all by the way. Best luck, there's a group of cougar flyers still on here or highbrid cougar-winds, they are all great sources for real data as I'm just wrapping my 4 year build up still.?
Greg Blake