No,that\'s not a ridiculous mix at all. It\'s already being used by lots of us. It\'s called JB-X, named for the first person to suggest it. Click on the reference material link at the top of the page and read through the cookbook. You\'ll find this mix listed in there.
You\'ll want to do something along the lines of 7 parts RM to 3 parts NPA. That seems to be the starting point for mixing, and you can adapt your mixture from there depending on how it goes for you.
Bookmarks