1/2"
Your picking up what I'm putting down. Many guys around here run 1"-1 1/4" set ups. Plus
@kingOFgEEEks just found the plastic bushings. I was considering GM automatic shift linkage white bushing, shaved down. The plastic jobs are easy to thin out when you need to. Aready have some cupped washers to fit my drive. The old labels make nice shims. The steel bushings and brass ones are a pia and don't fit spun centers. Plastic also expands easily.
Got this small electric motor all set up for dressing wheels down.
My machine has a 2 3/4" swing or clearance. It can be opened up another 1/4". This leaves me lots of cheap options. My chain clamps also fit 180 around. Need to tighten up the vice hole and mark the opposite side with a degree scales. Been using my angle finder to set up.