25 years ago or something, I bought the Octalink specific crank puller. At the time, that's what I had on my bikes. At some point, I pulled the little disc off and used it as a regular puller for square taper. It's worked fine for both for all that time.

I did lose the little part that makes it work for Octalink. Like decades ago. I used a flanged nut, not sure of the size, but wide enough to contact the bottom bracket but narrow enough that it doesn't contact the crank. I hold it in place with an m5 bolt.

It works perfectly.

Pennies, dimes, and washers tend to never be the right size and get deformed when used this way.