Hi, this was really interesting to see. I have a 2018 SB6 (small) and have been thinking about a mullet conversion as well to give a bit more rolling speed for racing. I love my bike how it is but I have to work so much harder pumping and popping over things compared to my friends on large 29ers but I enjoy the playfulness of the smaller rear wheel compared to SB130 and SB150 I test rode. I scribbled some calcs down re the fork and came to the same conclusion re 150mm travel and have noted your offset choices...