I'd like to put in few more comment on foot strap positions /fin size, etc..
mine always all the way back with relativelly large fin, if you have problems/tail lifting,
you have choices: moving mast track forward, smaller or better fin, moving
foot straps forward, specially front ones (makes your stands wider),
all of those things will de-power you set-up but will give you better control,
so final result could be actually a better avg. speed,
as your tecnique improves, you'll be able to move all settings back again.