advice on upcoming social documentary project?

[kajiki]

Folks, I've got a project coming up which entails following a couple of high rollers around; people, parties and places essentially.
I've budgeted for the purchase of a couple of newer bodies (I shoot a couple of D70 bodies right now), and was considering a pair of D700 bodies......main reason being, I plan to shoot the 35mm F1.4 and 85mm F1.4, available light only. One of said HRs is a bit of a photo nut too, and will probably loan me one of his Leica M bodies.

Am I right in thinking that the D3 is better sealed (than the D700) against the ingress of moisture? - reason is, jumping out of cabs into clubs entails a rapid change in temperature/humidity, which I know affects lenses the most....

Otherwise, I might just shoot a tiny bit of lit stuff, being as it's all going to be on the hoof, I'm thinking about these brackets like Stroboframe, with the biggest practicable softbox on top? Is there a general rule of thumb guide as to the dimensions of the front panel of the 'box, in relation to the lens-to-subject distance?

To all intents and purposes, I'm going back to being a pap, but the pix are for a private party only, and a visually literate one at that.