Sorry to hear of your squealing drive belt. Since writing the bit about laser aligning the rear wheel for The Bulletin I have found that 100% straight rear wheel alignment isn't everything with belt alignment and sometimes it has to be sacrificed a little for belt alignment. I have found that if you remove the LH rear shock absorber you can get a long straight edge (1 meter) along the edge of the bevel box sprocket and the rear wheel sprocket. With that in place you will see what needs moving where to get everything aligned perfectly.
The rear swing arm LH pivot seems to need to be adjusted to almost touching the bevel box pinion to get good alignment and some belt clearance to the BB pinion guide plate when running. This was to the extent that the plastic bung was often left out of the LH swing arm pivot at manufacture. You may need to replace the corroded swing arm bearings if this was done on your car. If the belt alignment dictates a large deviation for wheel alignment, the bevel box mounts will require repositioning, not so difficult with Phil Bleazeys mount but more of a task with an NVH mount.
It really isn't a simple task to get the wheel aligned and the belt running true, usually some compromise is required. When laser aligning my rear wheel it is about 1/4" off to the right over the length of the car on the front number plate target to get everything running right with the belt, acceptable I think. The guide plates are just that and shouldn't have the belt running hard up against them under any conditions, front or rear.
