RE: Warbirds & digital servos ... Worth it ??
The nice part about digital is that it has full power at center where most analogs do not. That way surfaces are not deflecting when they're not suppose too. I use the hitec HS5645MG with no complaints. Price is reasonable and their ability to be programmed is a major help for many special situations.
As far as flying a warbird and a difference, hard to say when precision flying is not really a warbird strong point. All the servos you have listed are excellent warbird servos and little difference would be noticed.
I have been told that the 8411 was not designed to hold a surface in position (like a flap) for a long period of time. Apparently it cost the owner a BVM F-86 when one flap failed and the other stayed down-ouch !
If I was to set your plane up with your servos, I would have 8411's on the elevator and rudder, 4721's on the flaps and ailerons, and 9202's on throttle and retract valve. The 9202 could be ailerons if you were out of the 4721.
If I had to buy new, I'd go with the Hitecs.
S1