I have plumbed a small holding tank in the return line from the "K" valve. This tank is always full after the first start up of a weekend of racing, and does not require refilling.
My primer system is basically used to keep the engine running at the top end of the track. My fuel tank is long and narrow and when braking after a run all the full runs away from the pickup.
It can be used to restart the engine at the start if starter as waved off a start because of a problem on the track.
I have a push button on the dash that runs the primer pump which takes fuel from the bottom of the tank and injects it into the distribution block.
This produces enough fuel to keep the engine running to make the top end turn under power.