Thanks for the advise going to start off without it and see how i do.
That's the approach I would take.
FWIW, I think the two sizes of blocks people commonly use are 40mm and 57mm, so the difference isn't very big either way.
There's a related post about boom/deck height (and the reason you want the shortest distance) I made in a thread about the Forstman boom that might be interesting:
http://dnamerica.org/forum/index.php?topic=1061.msg3529#msg3529