Bud, try to use calipers that push from both sides if those dont, then they have to float on pins.
The ones that have pistons moving both sides only have to be parallel to the rotor, and sort of centred.
May as well use a good floater, a lot lighter and most modern calipers use a narrower brake rotor area, not the best for your rotor and they may not handle the thickness.
Ducati and Yamaha floaters should fit your 6 bolt hub you may need need to build a centering ring or one with a bit of offset (spacer) and centering nub..