From experiance I have found that finding the perfect FD height can very a lot depending on crankset and gearing sometimes as low as a half mm up to about 4 above the big chain ring. Normaly I just find the lowest point at which everything works good and raise it just a bit. Your setting of 1.7mm sounds about right for most setups. If you found a hieght that everytning works great at with in reason I would just leave it and stop worrying.
Last edited by zukahn1; 04-01-12 at 06:25 PM.