You're right those are tiny offsets and those are the ones I used.They do make the tank look better but in my opinion at least another 1mm is required on all the rollers, possibly even more when the rear idler is raised and it's diameter increased by 1mm. I know increasing the idler diameter will detract from scale but I still think it's the lesser of two evils as it's stock diameter is to small.
Here's some pic's of the work done a while ago and you will probably agree with me that more raising is required.

All the best,

Nick.