Hydraulic lifter preload

Hey guys.
Just wondering about hyd lifter preload
Adjustment.
My 68 383 has comp adjustable roller rockers I adjusted the aprox 4 -5 years ago, I noticed after the engine warms up I can hear a few lifters clacking ( I hope lifters anyway lol)
I'd like to pull the valve covers and re adjust to make sure..
Should I load the lifters with a little more pre load? I can't remember what I set them at initially.
I don't care about leaving a little power on the table.
Thanks for any advice