The only T3 I threw was a Gstar. It flew great, exactly as advertised, but not longer than a Teebird. Kind of got there quicker and lower.
This. My only experience with T3 is Gstar, but I wasn't very impressed. Didn't have the same great hss as a good champ Teebird and it was just sort of clunky. My birds get less use now after I got turned onto the Verdict...when it isn't enough I just move up to a driver like OLF or Viking or Saint Pro or whatever. Between the two, I'd just pass on the T3 and use the Thunderbird. I can't think of a situation where the T3 really excels over anything else...not a horrible disc or anything, just doesn't really add much to what was already available, imo.
Please do yourself a favor and do not worry about disc overlap. Play a couple runds with both in your bag. Throw the same shot with both the t3 and Thunder. Throw annys with both. Throw hyzers. If one does something you like and the other does another shot well, keep them both. If you find you don't reach for the t3 after a few rounds, take it out.
^^^ Really this. Get to know your discs...try everything with every disc you have and you'll be a better player. Molds don't always matter that much in the end if you can work with what you have available (to a point).