The fuel pump “rating” means almost nothing.

If you haven’t done it yet, you need to plumb a fuel pressure gauge into the line up near the carb and see what the pressure is at wot.
If it’s less than 5psi, that’s the first thing that should be addressed.

I would be sure I had at least a 3/8” supply line from end to end, including the pick up.

Since you’re talking about doing prolonged wot operation, I would be upsizing the tank vent as well........ I’d do a 3/8” vent.

You need to determine for sure that the fuel supply is keeping up with demand before trying to fix the carb.

One more thing, where do you have the floats adjusted?

The power valve rating should have no affect on your problem, at wot they should all be open.
The pvcr is the feed hole in the metering block supplied by the PV.
It’s likely they will need to be enlarged from what they are now so that they contribute more enrichment when the PV opens.

A couple of follow up questions......
-What valve springs are on the heads?
-does the a/f meter show lean fairly quickly after you go to wot, or does it take a little time for that to happen?
-Does it seem to get suddenly worse when you reach a certain rpm? If so, what rpm is that?