You can use any dial indicator that will allow you to read the piston height while it is in the bore. Of course you need to figure out a sturdy and accurate why of mounting it to the engine block. For example a spacer and a rig that uses the 5/16 head bolt. This would be done with the head OFF.
The only thing the Official Tecumseh Tool does is to allow you to do this job with the head on. I have that tool, but I always end up doing it with the head off anyway, because when I time it, I still have other stuff to do to the engine, and haven't buttoned it up yet.
Another way I've seen it done is to use actual feeler gauges and set them on the piston to equal that .035" "before" Top Dead Center. Study that video a few more times, and learn about using ohm meters, or what electrical continuity means, and what it takes to move your points plate to make stuff happen. Honestly, it is a very tedious adjustment to make and I've been frustrated at times, but in the end, you can get it done.