If you believe it is starvation of fuel when secondaries opens I would address that issue first then. Do not remove the small brass filter in your Holley, they serve the purpose of securing that your float valves remains free of any contaminants so they do not fail open. If those filters gets blocked then the next natural step is to find the source of the contamination. The standard supply pipe in the fuel tank is in fact marginal to support 500hp. I exchanged mine for a 12mm and I also use the Rob MC performance mechanical pump. This was part of my long troubleshooting and exclusion of potential reasons for the misfire. Until I finally realized that the misfire was not a misfire but valve float. Everything in the engine was new incl. the relatively heavy hydraulic lifters which apparently needed very stiff valve springs to handle the inertia in those lifters. I bought brand new assembled Trick Flow heads and the cam manufacturer approved the valve spring load. It turned out that he was wrong!! I needed to go one step up on the springs to be able to rev past 5200-5500rpm. Lots of lost sleep and lot of wasted time because I trusted his words. We learn as we go along.........
If you floor the pedal your secondaries are forced open on you double pumper. If you have a fuel delivery problem it could possibly be that the secondary float bowl struggle to keep full and if the fuel pressure drops at high demand (high rpm) you then obviously have a fuel flow problem. Not enough fuel available at the pump to maintain a stabile pressure or a restriction between the pump and your carbs float valves.
Possible causes: Lines/tubes inner diameter to tight, bended/flat hose or pipe, filter clogged, fuel pump failed or improper and of course the supply line in the tank.