Greetings Mark!
i still have a backup of perceptol,but i cant really use that for N+ N++ cause it would increase grain,and thought to try something different.
I would expect Perceptol to produce results finer than ID11 at similar contrast. Have you given this a real go yet?
As to plus development (more contrast) increasing apparent grain, that's not really a developer issue, that's just life with silver based negatives.
Staining developers try to minimize this effect by using not developing the silver as much and relying on the stain to carry some of the load with regard to building contrast. You may want to try something like Pyrocat HD or RolloPyro and see if that helps. These are typically very sharp developers too.
im satisfied with tmax 100 all together,but with ID11,bit more contrast sometimes would be good( i couldnt get N++ out of it,selenium helped)
grain is not a problem with 4x5 for me with my enlargements till now,but im planning to make bigger enlargements,and some finer grain would be good too..
Why couldn't you get plus with ID11? Was this judged at the print or with densitometer or...? Did you develop longer than for N+?
Contrast is a dance between developed film and the paper you are using to print. For example high gloss paper grade 2 will have darker blacks than grade 2 matte finish paper. That has a big effect on perceived contrast.
Even if you had trouble getting Tmax 100 to ++ changing to grade 3 from 2 should have solved that issue so I'm not understanding how switching film developers is going to fix your print contrast problem. Did a harder grade of paper fix the issue?
so all together,yes..some contrast,sharpness and finer grain would be good,
its not that bad with ID11,but i hope it could get better

Thanks!
I'm sure you can get better. These questions are here to help you look for the right things to fix.
For example sharpness and fine grain are characteristics in opposition. ID11 stock is somewhat solvent, which means the edges of the grains get smoothed a bit. ID11 1:3 is much less solvent because of the dilution so the edges don't get rounded off as much and that dilution produces a little sharper images but it looks slightly grainier.