I've taken my 72 El Camino to bare metal and will need to seal the drip rails after priming. What is the best product? I've read recommendations for 3M's Drip-chek sealer and SEM's Catalyzed sealer. Any other sealers better than these two?

Drip check is to thin to fill the gap. 3M makes a heavy body chaulk i us with a chaulking gun which works terrific. Heavy body to fill yet very toolable with your finger.