Good luck- from memory, I have about 20thou float on the idler, but far as I can tell, the only lateral influence on it is from my dynamo belt alignment, I figured it best to allow it to find it's own happy place.... which reminds me...
Two things,
1) I've been meaning to mention this for a while, but.
..make sure your oil pump mount screws are tight, when I was in mine to check the belt, I noticed they were a bit 'loose'...
, but are allen screws- I have to remember to order some proper studs with lock-nuts...reason for lock-nuts, is so that they can be backed off then nipped up to remove the stud, and on replacement screw the stud in to the full extent of the coarse thread, and use the fine thread(carefully) to make it nice and snug, and fine threads are less likely to vibrate loose. As these are some of the most crucial fastenings on the bike, it's worth getting right- note to self
2) forget it- I did...I think it was a personal thing....