The mid-pro was the only type that had zimmerit. There was towards the end of the mid-run, zimmerit was nolonger applied, so you can get away with a Tiger without Zimmerit. I would go this route, three tanks in 27 yrs is not a good track record for tackling a zimmerit project. If you were to do zimmerit, may I suggest www.ipmsstokholm.org, a great article can be found on zimmerit applications, do a search under zimmerit.
With all the indivdual tracks, go slow my A/C friend