I know that a three carb setup sounds really good, but given the obstacles you’ve already encountered, is it really worth it? You’re not going to see much if any power gain on these old Stovebolt's without investing a boat load of money. In my opinion, you would be better off replacing the existing carb with a carter and avoid any future headaches.
If you want to go down this road, posting your issues in the HiPo forum will get more reply’s. Not everybody follows the Project Journals.