I have assembled about 6 of these.
I start with just the bearings in the block, lay the crank in and measure the end play. I’ve not seen any measure measure than .007” Typically .004-.006”

So are you sanding these to your spec?

Next i put the middle cap on with the bearing, hand tight on the bolts and tap or pry back and forth to center the cap. Measure again. It should end up at the same clearance as you had with no cap.

It’s important on these to have the top and bottom shells contacting the thrust face (rear) of the crank equally. So that one half isn't taking all the load.

There is also a nice little mod that can be done to the bearing that forces some oil to the thrust surface.