You are right, let's keep 'em confused with massive amounts of info!
I don't quite get what TH told you. Did he say to slide the prussicks towards the hammock from where they would be if the stock rain fly was centered? That's a new one to me, but no reason it shouldn't work I guess. Except the original directions were to first adjust/center the stock fly, and hook the pad/UC to the prussick hooks at that spot. It seems to me that pushing the prussick hooks down to where the rope comes out of the nylon is adding possible variables for tensioning, and even conflicting with the original directions. And it seems to me, no expert, that this would be too loose and cause a gap, ESPECIALLY if you laid any clothing on top of the pad( more weight to pull it down). Now this is confusing.