Zero Camshaft Endplay

It’s pretty basic really.
The cam sprocket butts up against the forward edge of the step on the cam.
The remaining space between the back of the gear and the rear step on the cam needs to be greater than the thickness of the plate.
If it’s not, then the plate is getting squeezed by the sprocket as the bolt is tightened up.

This can be test fit on the bench before the cam is even slid into the block.
Slip the sprocket on the cam, and using an appropriate combo of washers/eccentric, etc, snug the bolt up.
You should be able to slip the thrust plate between the cam and the sprocket.
If you can’t, it’s not going to work.

A few minutes on a surface grinder with a magnetic clamp, and grinding on the front side of the thrust plate in an area slightly larger than where the sprocket rides, to have about .005-.007” removed, and you’d be all set.