I often put a coupe bolts in the crank flywheel flange, and turn the engine from the back to make sure the degree wheel stays in place on the front. Sometimes I help someone time a cam, when they get the comp set out I always turn the engine from the back. That or I am very careful to turn the engine the same direction, and use a dial indicator to find TDC like what was mentioned. The comp set doesn’t work very well with a piston stop if it has any slop.
You can get a Mr gasket 2* +\- key if the timing needs to move 4*. It is a 2*, but moves the timing 4. I have modified it for 3* before. They use to be a lot cheaper.
https://www.summitracing.com/parts/m...yABEgLlH_D_BwE
On a timing chain engine the actual running ICL number will be retarded from where you set it. Especially true on a double roller set. If you are targeting 109, you’ll want to shoot for 107. The link belt chain is probably a little less. I always add 2 on the advance though unless it is a gear or belt drive.
It isn’t unusual for 3 way keys sets I have had moved the timing twice the advertise change. Just like what you set did.