360 j head valve stem diameter?

That's my plan, getting everything together for a mechanical cam swap. As far as the rocker movement, I thought that as long as the aduster is in the right place ( crane says 2-3 threads showing on the bottom side of the rocker) and the pushrod is the right length then everything is good? Since the rockers are shaft mounted the pivot point is the constant, So it shouldn't matter which side I take up the clearance on(ie. the lash caps) If I am thinking this wrong please straighten me out. So what is the intended use for lash caps? I thought they would give me a larger surface area and protect the valve stem? Without the lash caps I would have 6-7 threads showing, I tried running it this way but I took them back off because I was afraid of snapping an adjuster since it had so many threads showing. I will get the right pushrods if there is a chance of damaging parts. Thanks for the replies!