How many grams weight for mm cartridge?

Thank you so much for all those responded - you guys are a great source of intelligent info! 
  
  I don't know much about cartridges as you must have guessed.
I bought the Denon TT used and the guy said the cartridge is Shure V type that is pretty old design. I don't have manufacturer's recommendation so I will just leave it at 1.7 grams then - it sounded better than .5 grams.

  

I think you are right - it is V15 type II, with small styli. I will use 1.25 as you suggested. Thank you madness!