Per the T-top and casting, I've never been on a boat (other than a drift boat) where people cast over the middle of the deck. We always cast one off the transom and one off the bow, but with the lines passing over the water not the deck. Therefore the T-top won't get in the way.
One symptom often faced is due to the wind... the outdrive always drags slower in a wind drift so a righty or lefty off the bow has the wind on his opposite shoulder - OK. The guy trying to cast off the end of the transom in this case is getting the wind onto his casting shoulder - TROUBLE.
In this case, I find it best to use a water haul to load the rod in place of the backcast and let the drift of the boat extend the fly line before stripping so you're really getting the same coverage.
Or the guy in the back can cast parrallel to the centerline of the boat along one side, making sure the guy in front is clear. This is a little more trouble and the cast cast to bite into the wind, but it works almost as well as the water haul method.
It feels like the guy in the back is disadvantaged because of the wind issues, modified casting, etc. Actually, because the guy in back does not have to pull the fly before it goes under the boat his presentation can make up on the back end what it lost in distance on the initial cast. I'll take the back if there is any drift at all, even when the wind is howling. Of course on a bluebird day nothing beats the bow.
Anchoring actually negates this tailgunner's benefit, and in most cases reduces the area you cover and the fish you catch. There has to be a distinct fish related reason to anchor or I prefer to drift.
Anyway, got carried away there - I just meant to say you need another excuse for the spin rod :hehe: (kidding)