Well I cannot really speak on behalf of these spools on honda motors, I can say the spool characteristic on the flat sixes is negligible between 28’s and 30’s. maybe 150-175rpm if that, and so small that’s it’s far outshadowed by the additional power made on the p-cars over the 28’s.
I have no idea how close tot he choke you’d be on a 28 in your setup that may or may not show the necessity for a 30r comp wheel.