For caster fans,
consider only 3, it’s more weight per wheel, thus moves but further resists moving, and no leveling required anywhere you move them
I also tilt mine back a bit, by putting a 2 x 4 flat above the front wheels, raising the front 1-1/2", which aims the tweeters up to seated ear level, and alters the angles of reflections off the floor and ceiling, as toe-in alters the reflections of side walls.
you can see the bottom here
my skirt acts as anti-tip protection. The old glides do not touch the floor, I just left them there.
These wheels are dual wheel furniture casters. I tried several ’better’ casters, I found dual wheel axels wobble far less than single wheel axels, I put these back on.
The wheels came from the bottom of my JSE Infinite Slope Model 2’s.
They had a flat bottom, no skirt. I changed them to 3, moved the rear wheel to the middle, and then added anti-tip blocks in the rear corners, just above the floor, they hit the floor if it tips while moving.
btw, I tried spikes with the JSEs, I heard no advantage, they are quite limiting.
ps, they are often shown backwards, the tweeters should be on the inside edge due to their narrower dispersion. I loved them, a friend has them now, I missed my horns and wanted to get back to tubes.