I'd say OS or Ninja too man. They tune so easy and pretty much run no matter what. I have 10 gallons on my VZB and about 8 on my other VZB. Never had any problems and im running all stock. Both have the original p/s, changed rod after break-in and threw in ceramic bearings. Yeah they are a bit high priced, but in the long run you'll get your money worth. Im sure a lot of guys could 2nd that. Im actually thinking about a ninja for my next mill as well or a os speed. That ninja has my eye. They honestly do rip and for $330-350 it's worth it.
Good luck with your choice and let us know what you end up with.
