Bill, that's an interesting site. Cool tool that I didn't know existed.
While looking around on the site I found circle fly cutters and an adjustable circle cutter using a drill/rotary tool.
https://www.aircraft-tool.com/shop/d...?PRODUCT_ID=5B
https://www.aircraft-tool.com/shop/d...PRODUCT_ID=HC1
Really have options that I didn't know about.