Personally I prefer the forearm dump. I have another suit with an upper arm dump (on the outside of the arm) and it is definitely not as easy to exhaust.
As for the forearm real estate... my forearm dump sits on the back of the forearm and I wear my compass (when I can find it) on the inside edge of my forearm. I use the goodman handle as a thumb grip... i.e. not with the ballast on the back of my hand.
As for the forearm real estate... my forearm dump sits on the back of the forearm and I wear my compass (when I can find it) on the inside edge of my forearm. I use the goodman handle as a thumb grip... i.e. not with the ballast on the back of my hand.