I have made a few for R2 & R3. Would need detailed measurements and pics of bottom to make one for R4. I assume it will be very similar to R2/R3 but wider.
Can you buy the caster base or is it a DIY job? What decent £30-50 HSFs are compatible with the case?


Painted and use cabinet door / drawer silencers on top of base for case to set on. Next one the front will use a 30mm and a 60mm wide laminated together with a 45 degree angle on double thickness side. Either threaded stem or smooth 20mm stem casters with 40 or 50mm wheels... usually7 40mm. Your mate's mate can use his glue of choice.