Looking at a new wakestyle board im 5"11 and about 85kegs. I normally ride a 136 misfit. For a wakestyle board should i go to a 134 or 138

Im the same dimensions. I ride a billy 139 (actually 140) sick board! Tried a tranq but felt a bit big. Go the bigger size especially if your booting it.

Yer sweet cheers mate

Same height and weight as you and ride a 141 LF echo and wouldn't want to go much smaller.

youll want the 138 or bigger

you want the bigger size to account for less upwindability (due to the rocker), and also just because you simply have more control over the board edge with boots, so you can hold more power (and thus have more pop) with a bigger board

It will suck more power than you'd think with the rocker.
Try to demo or try a friend's first, you might need a bigger kite if it doesn't get strong where you are or the water isn't flat enough.

I'm the same weight as you and ride a 145cm. I wouldn't go under 141 that's for sure.

Id go minimum 141. I find 142 perfect for me at 80kg. You could go 141-144 and be good in that range.