408 hyd roller, too much spring pressure?

It's on the high side for those lifters.
I bet you hear them pump down after down, tick tick tick...one by one...how do I know? Cause I have a bit less seat load on mine @130-135 lbs...but less open than you.
It's been said 130 was about all you want to run on them for seat with an iron core roller with open around 330.
Preload was stated ... up to .090
Should not have ticking on start up.

Well probably that's the subtle sound remaining after startup.
Would a "slow leakdown" lifter like HGH 5006S Hughes Engines be an upgrade, or are all stock style Magnum lifters limited to around 130/330 lbs?

I notice that Hughes recommends both the stock type HGH5006 and the fast bleed HUG 5007 for springs up to 145/358 lbs (for instance for cam SER7076ALN8).
Wouldn't the fast bleed lifter cause more bottoming out problems? Or perhaps the limitation of the stock lifters are not only in the noise-causing bottoming out?