I will use the 605HD pneumatic because I have a set of main laying in the workshop, so I have only to buy the nose.
I am really short with money actualy

I am a bit concerned about the final weight if I use my OS 120.

I could go above 10 Lbs, that's a lot for a 605 HD

but if you use a pneumatic you save one servo (if you look at the mechanical already made in the DV it's difficult to route the nose retract wiring so a extra servo is use to retract the nose)