I have W-2 and W-5 heads..both oil via the PRs..
and the W-2s have EDM holes.. all I do is put a
1/16" NPT plug in the port in the block before
I put the heads on.. been working fine for a few
years now.. I do have restricted PRs.. I just
set up the W-5s and checked the oil flow yesterday
and it looked great.. both sets use the TD multi shaft
rockers