:*What are "the vast majority" of Indo-Greek maps you are refering to? I personally know only two published ones: one by the Indian Ministry of Tourism on Internet (minimalist), and now one by the "Atlas der Welt Geschichte", which visibly takes into account all available sources, and is probably more respectable as a historical reference. Any reference for this claim on "the vast majority" of Indo-Greek maps?
About "only verified administrative regions" for a map: a map is not only based on "verified archaeological data" as you seem to claim. Literary sources also play a major role. There is almost no archaeological evidence of Alexander's campaings in India, only litterary evidence, which are nevertheless the source for all the maps of Alexander in India. In the case of the Indo-Greeks, we have a combination of archaeological and very varied literary evidence (both Greek and Indian) relating their conquests, which is visibly the base of the "Atlas der Welt Geschichte" as well as my previous maps. 
"Dimita could very well be Vima or Vimaka." You failed to read the rest, which states that Vima or Vimaka is not considered as a proper hypothesis since the king is qualified as a "Yavana", an unknown occurence for Kushans, and the paleography indicate a 2nd century BCE date.