$75 Non-S Center Stand (complete and in great shape) from an inmate:
Thick mild steel bushings (snug fit)
1" .90 tubing cut to 33mm is a .05" larger than the 24mm tubing used with the center stand. No biggie. Dry fit:
Drilled 5/16" rosette weld holes in the center stand and filler tube so I could weld the bushing inserts in place for strength, in addition to welding the circumference of the butt joints. Welded, primed and painted. Not my best work (in fact it looks like shite), but strong, and works perfect.
Already had lots of tube and bushings, so only out $75. Sure beats $350.