I myself like lash caps for two reasons, one is as mentioned to get the rocker arm geometry (scrub) where I like it and as well I feel they help spread the load on a small diameter stem. But im under 7400 rpm and something really bad would have to happen to toss a lash cap off.

Ive always had longer valves, as edelbrock seems to run a longer valve vs oem in the small block offering.

Ive recently found myself in a spot where I needed to use the smallest diameter spring I could find but with a high spring rate do to the amount of porting getting semi close to the spring pocket.

If I had not already had the setup id of went conical.