I found a solution using MagTools, but it required creating two different metas. One for the Mule, and one for the char muling.
Set the main macro to /tell the mule "SALVAGE" triggering a "set state" on the mule with a "Seconds in state >= 15"
After telling the mule "SALVAGE" I used /mt give Salvage to MULE NAME
I couldn't find a way to have it switch states after it ran out of bags of salvage, Since I had no way of using "Item in inventory <=" because I couldn't find a way to have Vtank identify each bag, So it just goes into the MT "Unknown Command!" when it runs out, and after 15 seconds, the Mule char does a /r MOVE ON, Triggering a Meta State switch on the main macro. After that, it was easy, because the only other thing I usually mule are Peas and Little Green Seeds, both of which Vtank can Identify and use the <= command.
Anyway, Just wanted to share this in case someone else wanted to try it.
Thanks for all the help IB!
EDIT: I also have the mule char set up with a loot profile to auto salvage all the partial bags the Main Char gives it. It's not perfect, but its easy enough to unload the full bags and leave the partials on the mule manually, once i have a good number of them.