How does oil get to rockers with solid cam setup

MRL's setup oils the shafts from the oil pressure sender passage at the rear of the block but maintains the path from the block up to the rocker stand. Indy's kits use the same pressure port but either feed the heads directly and up to the rocker stands, or use a spray bar and eliminate the shaft oiling altogether. There's not much difference in those setups except for the spray bar version but I know you need to meter the oil that goes up because it will literally flood the top end. There' a reason the factory only has oil flow for a few degrees per head per rotation. It doesnt take much...