It would be ideal to get the runners equal length but increasing the diameter of the pipes would probably do more harm than good. This would slow the air speed down and then it would have to speed up. This takes energy, energy that could be spinnig your turbo.
I have a t25 on my a14. I get a couple of psi from about 2200 to 2600, then its full boost about 3000
I suppose a lot depends on the manifold design. Mine has two short ones in the middle too.

how much trouble was resurfacing the turbo flange? That's a good idea for getting all the pipes together.

Since datsuns have that lousy 2 port together exhaust design do we just cheat and make those 2 runners shorter? What if they were a smaller diameter or something to make them seem longer to the gas.