I run B40 up here in canada. Havn't had any problems, but u should not switch back and forth. The reagular diesel blend (clear) actually leaves deposits in your tank, fuel lines and injectors. When u switch to Biodiesel the build-up is removed and can clog filters. Put a few tanks in and switch fuel filters and never look back. Running B40 or B5 doesn't matter as long as B-somethin.
Biodiesel is already a mix. If u have a half tank of B40 then put in clear diesel, its still biodiesel, just maybe more like B10 or B20
I don't have a chip yet and was hoping when i get my SCTX3 that if I data log and send in a file that it will be easy to make up a tune.