I'm looking to buy a diamond plate for lapping my norton 4k/8k, and my Naniwa 12K. I wanted to see if I could also use the same plate to use as a bevel setter on very dull razors. People mention on here that the DMT diamond plates are good for lapping these hones. I think most people use a lower grit plate though, something like the 325 or the 600 grit plates.

Can I use a the 1200 grit diamond plate to lap the norton and the naniwa, and also use it to set bevels on ebay type razors? I figured buying the 325 or 600 would be too low of a grit to use as a bevel setter.

Assuming that I could use this plate for all of these purposes, would it make a difference if I got the 10 inch by 4 inch plate, instead of the 8" by 3"?

I didnt know if having an oversized plate when lapping, and bevel setting would introduce unwanted variables, such as uneven wear on the diamond plate or something.