Maybe he should put a glob of some heavy black wheel bearing grease on the end of both axles and then installed them to see if they are having that grease squeeze out or is there in a thin layer left between the axle and center blocks or thrust pins

You're applying logic to this.

I recommended a trial fit and he poo-pood that right away.

It's like he wants to install the axles in the housing once and only once.

Hence why he was asking how much to take off the end of the axles, thinking that there was a set amount to cut off.

He should know better than think that you're only going to do an assembly once.