Wammers did some detailed responses on this. I can't remember who he was helping. There is indeed another hole just before the TDC one. You don't want to be 180° out either.
Apologies if this is well discussed. I looked but couldn't find a thread. I've got the front cam lobe pointing to the injector side with the edge parallel to the guide visible in the oil filler hole & the locating flywheelpin is in & located...