Looks nice, that's been on my "todo" list for a while, I was going to canabalize the Fujimi 1/72 tractor.
For real world reference of carrier tractors, there is some great stuff at
http://www.news.navy.mil/view_single.asp?id=4271
http://www.news.navy.mil/view_single.asp?id=6061
Depending on if you are shooting for "realism" or duplicating the sketches, it seems that for the most part the tractors don't have diamond plate, but get coated with the same non-skid "goop" as the carrier deck.
John