Yamaha R1 rear shock alternative

I am gradually building a 1986 VF1000FF and the rear shock is needing replacing. I looked at the YSS option and thought I could perhaps find a cheaper solution. So I have found that the current Yamaha R1 has an adjustable ride height via a threaded bottom shock eye. My plan is to chop the bottom off the VF shock and weld a threaded adapter into the top so it can be fitted onto the R1 shock. This is a 2023 R1 shock and cost £58 on eBay it was taken off a bike being upgraded for track days. It clashes with the battery box slightly but I think with a slight modification and a smaller modern battery it should fit. I’ll will add an update when I hopefully get it sorted.