Ron in Sterling, CT
I agree with using 7, or an 8, and that a 6 will do in a pinch. I have a 6 and a 7 that I picked up at auction or at a flea market. Each for less than $35. A little cleaning, sharpened the blades and they wee ready to go. I use each of them 3 or 4 times a year, but when I need them, nothing else will substitute. $300 is a lot to spend on a tool that will probable fine limited use in your shop.
My 2 cents worth