how much if any adjustibility is there to the rear alingment ?

my belts are showing on the inside after putting on Z springs 20K miles ago. The tires were bran new. 20K miles later they are at the wear bars all the way across anyway so I'm not too diasppointed just want to do better for next time minus the exposed inside belt

thanks

 

the rear has a good amount of camber/toe adjustment, thou im not sure if it is enough to compensate for the z springs.