With any pump stronger than a 1250 I'd bet on the #4, provided there are no other blocks in the loop. If you've got 1 or more other blocks in the loop it'll take a extremly powerfull pump (MD-20rlzt?) for the #4 slit to be of much advantage. With a 1250 or L30 I'd say you may as well stick with the #1, even if you have no other blocks in system.
|