When I bought my CSX-T years ago, it had gear oil in the trans. Switched it to 5w30 when I put the new engine in it, and never had any issues. Well, at least until after I swapped it into my old Daytona and jumped a curb on a foggy night resulting in a broken 16" pumper wheel, bent control arm and k-member, and a cracked transmission case. But that's a different story.
Anyway . . .
That is a thought. The new clutch has a rather fat hub in the middle. But I did try pushing in the pedal to a few various depths during the test drives with no change. The old clutch would release by about 3/4 of the way down. But I'll compare it to the old disc and see how it stacks up.
The other thought I had tonight- Is it possible that the flywheel has been turned too much and the throw-out bearing is reaching the end of its travel before fully depressing the fingers on the pressure plate? The flywheel seems plenty thick, but I don't have a good way to measure it, and I have no idea how many times it's been turned. I just grabbed the best looking one off the shelf. I looked through the service manuals and it only gave specs for runout, nothing for overall thickness. But I notice that Rock Auto lists flywheel shims in 0.025" and 0.050" thicknesses.