TDC has to be lined up when # 1 is on the top of the COMPRESSION stroke , so .. you look at the valves when the balancer says OT.. If the valves are BOTH closed , you are on compression.. if not, you are 180 degrees OUT/OFF.
The old fashion way was to put your thumb in the plug hole and feel for pressure as the piston was coming up on compression, then just line up the OT mark..

Either way....