RE: McCoy diesels
Dan, For removing my cylinder heads without damaging the anodizing, I made a tool using a 4" - 5" length (non-critical) of old rubber garden hose split up from one end about an inch or so, in four equal spaces. I found an inexpensive adjustable stainless steel pipe clamp that fitted over it. I simply push the hose down over the head (the contra adjust vee slides up one of the slits) and tighten up the clamp to hold the cylinder head with friction. I poked a hole through the hose at the other end and pushed a 4 inch long by 1/4" dia.alum. bar (totally non-critical) for torqueing the hose. It works every time, and not a scratch! Your pic of the metal OK tool is even better, however I'll wager that unless it's very tight, it will scratch the color anodizing if it slips any at all.
Also, I use a little smaller pipe clamp tightened over the sleeve's threads (of course, after removing their cylinder heads by above method), to hold them securely while turning them - with no danger of messing up their nice cylinder head threads. Not needed for D-C sleeves that come out easily.due to their design.
Others have probably already thought of these gimmicks, but they've helped me preserve the delicate exterior of my diesels! FWIW!! Bill