Just an update...
Tires are mounted. Tubes were dry rotted. Local tire shop chewed up my rear rim. JB weld filled the marks. Bought and modified a harbor motorcycle changer, as local bike shops want $70 per tire. Buying a cheap balancer.
The rear tire is a particular pia to mount.
I haven't got them on the bike yet. Waiting for new tubes and the balancer.  
The rims are not tubeless.
The gs450 sprockets and rear brakes are a fit with spacers etc as otherwise detailed here.
A wide tire is difficult to mount on the rims.
For the mod to the changer, check the you-tube site.
You definitely need to modify the front brake rotor or caliper. Do a search.
Hope this helps.