If you want to confirm that the static timing is correct before you fire the engine, the inductive timing light is not the best tool. A test light connected between the wire from the coil neg terminal to the distributor points (disconnect the coil end) and ground is a better choice. With the points closed the test light should be on. Rotate the engine until the timing marks are at 10 deg BTDC. Adjust the distributor rotation until the light goes out / points open. Tighten the distributor and check by rotating the engine one full turn and watch to confirm that the test light goes out when the timing marks hit 10 deg BTDC. Adjust if necessary.
As Scaramoucheii indicates, an inductive timing light is best used on a running engine and is excellent for making adjustments in the timing (once the engine is running) and checking the operation of the advance mechanism. Not the best tool for setting static timing on a non running engine.
.
