I had the ARP bolt set so intended to use the header set but as said you can't get a ring spanner on them. I used socket heads, all were ok except one, it was marginally too long and too wide. So I ground it down in both directions. You need to insert this bolt into the header before offering up to the head, the slightly oversized hole allows it to be inserted all the way in, then offer up. Yes was fiddly but worked for me. I used a long Allen key which I also ground so as not to foul the header.
I used VHT which didn't survive cam break in so read all related threads on that topic, if your pre break in.
Technical Area for all the problems you have in the garage