Hey guys. I am in the process of converting my 21 speed hybrid into a single speed with a flip flop hub. With non machined deep v wheels, for example retrospect or pure fixed cycle wheels, would brakes work very well on them? Or would it be better to find different wheels (non deep v)? Thanks guys!

No, braking on non-machined wheels will be terrible. Just get the H plusson SL42's and use your current brakes.