Make a super simple junker first of the approximate size/weight.
Then when you get all the trim settings, make it scale.

My vote is to go with a heli head,
heres a 3 blader
http://www.heli-world.com/Merchant2/...ct_Code=CN1113
and the matching swashplate
http://www.centuryheli.com/products/...?currentid=199

mick