Timing and TDC problem
You found TDC with the piston stop. You new mark for TDC is 1/2 between the 2 marks on the balancer. You then set the adjustable timing pointer to the new TDC line. Now you would unplug the vacuum line from the distributor and plug it. Set the dial on the timing light to zero. Point the timing light at the new timing mark and pointer. You should have a normal reading of 10*-12* BTDC.