I was putting a cylinder had back on a Land Rover today and remembered this trick for torquing the head bolts. The tightening sequence is 20nm +90° +90°. I don't own an angle gauge and space is limited near the firewall anyway. After putting the 20nm on all the bolts I man them with a straight up and down line with a crayon so I don't lose my place. I put a small zip tie around the top of the socket and orient it before each +90° so I can easily see how far I went. This is very helpful when there isn't room to swing a full 90°.
This tip is less useful with odd angles like 40°.
