I thought Joji's idea to use a motorcycle clutch tool for the output shaft bearing/seal nut was a clever idea, but I thought it would be better to make one out of a PVC plumbing fitting. Unfortunately, Lowe's didn't seem to have anything i the proper diameter (for my NG3, it needed to be about 2.5"). My next stop was Joji's idea. But I fat-fingered the order and I got two. I tried it and it worked just like Joji said! No reason for me to spend ~$90 for that really nice wrench from r.d.
Here's the one I got (
https://www.motionpro.com/product/08-0008). I'll sell it for $22, I pay shipping.