Did something similar for my DL1000. Made some quick & dirty uprights, far cruder than the pic above, with 90 degree "V" notches rather than round holes. Then I bought an 18" piece of 20mm shaft stock and a pair of open 20mm ID bearings from McMaster-Carr. The bearings rest in the notches. Wheels are balanced with MotionPro stick-on weights to higher speeds than I care to push the Strom - all is good.