NADA type benchmarks for heavy truck

[vtecmanager]

Long time lurker and past frequent poster here guys. I've decided to take a turn in my career. I had previously worked about 15 years in automotive parts management (Honda, Hyundai, Mazda) and need a little help. I decided to take on a medium/heavy duty fleet maintenance company's mobile parts inventory (100+ trucks in 20 states). I am also starting to help manage our parts inventory in our brick and mortar shops. I was wondering if there were something like NADA parts management guidelines/benchmarks for the medium/heavy duty side. Keep in mind that I'm not part of a brand/franchise. This company DMS doesn't come close to any that I have been on (ADP, R&R, UCS, and Dealer Track) in a bad way and reporting/knowledge of inventory management is non almost non-existent here. I guess that's why I'm here! I know how to get all of the figures needed, but I need a baseline. Thanks for all your help.

BTW...I have both of Mike Nichol's inventory books from the auto days...the yellow one and the white one!!