From your post I read you will not be racing the car. Then upgrading synchros will not be necessary. At this point you are soley in it for the ratios.

Mechanical vs hydraulic.A hydraulic line beats 2 rods, a Z bar and 2 pivots any day and it's immune to a transmission moving around and can be routed anywhere. An internal slave failure? This is a valid concern but so many cars have their original internal slave in the junkyard as the rest of the car fails around it.

Sounds like clutch feel is important to you. In that case Centerforce. It is the lightest pressure plate on the market but the weights take up real estate where the hydraulic throw out bearing wants to be. I just installed a hydraulic release behind a T56 Magnum 6 speed with a Centerforce clutch. McLead recommended to remove the weights for clearance. I mocked it up, looked like it would clear but chickened out and removed them.