R,
A couple of clarifications.
The rear(feed) pump has the smaller piston, and the front(return) pump has the larger piston. Dry sumps need more pump capacity in the return circuit to clear any wet-sumped conditions.
The only things directly fed by the pumps are the rod bearing and the rocker arms.
The feed pump delivers the oil only to the rod bearing, and the oil slung out from there performs splash-oiling of the main bearings and cylinder/piston/rings.
Then the return pump picks up the oil as it runs down into the bottom of the sump, and pumps it up to the rockers, and then it slings out from there and splash-oils the valve/springs and pushrod, and runs down the pushrod tunnels on to the tappets. It then drains thru the tappets and the drain holes next to the tappets, and collects inside the timing chest, where it bathes everything in there, and when the oil level in the timing chest reaches the return hole behind the distributor drive gear, it runs thru that hole into the oil tank to start its cycle over again.