Agreed that hyd lifter gets it's oil pushed out when parked at an open position but the pushrod could come out if running very little preload. Some run 1/2 turn preload on an adjuster directly on the pushrod which is only .020 preload.

Could run 2 full turns for .083 with less chance of this happening.

More preload could also help, just starts getting risky if your valve/piston is close and the system loses control at high rpm. (though that's obviously a problem either way, could crash valves if it lofts and there's a ton of preload).

Doesn't change much geometry on a shaft system, well at least rocker to valve. I suppose too many threads below the rocker on the adjuster isn't the best thing but from the photos it seems like it would be ok.