Thanks City Farmer:
My Ford parts guy thinks that the sub frame weight IS included in the Ford hoe manual published weight, which in the case of my 750 hoe (10') the total weight would be 2200 lbs.
I am not so sure, because that hoe, with bucket, and stabilizers is one beefy hunk of steel.
Even so, if the total is 400 lbs. more (2200 lbs + 400 lb. sub frame) I am still OK with that.
Your response is greatly appreciated!