Hmmm I've done a hunt around and it seems that there isn't a tripod collar for that lens (if I'm wrong someone Nikon please correct me).
It makes things a little more tricky, but not too much. The reason I ask is that the RC1 flash heads are fairly small units and the ring grip that they come with means that they are put right at the front of the lens. Now this isn't a bad position, but it does mean that you've less distance to diffuse the light and less space to mount a diffuser to the lights themselves. Personally I would go with a speedlight design flash, a diffuser (Lumiquest softbox normal is a good starting point, though some larger handheld ones are also on the market), off camera flash cable and a flash bracket.
This gives you a setup which you can easily use to position and control the light, but also means you can invest your money in a flash that you can use in almost any field of photography - whereas smaller macro flash setups like the RC1 tend to be a bit more limited in power and in the scope of addons you can get to use them outside of macro work.
For brackets there are loads, but most are aimed at portrait photography and not as ideal for macro. My preference here is a RAM Mount set of duel sockets and duel ball heads, with a ballhead and 1/4 screw mount on each end of the constructed "arm" (this gives you a screw to bolt onto the base of the flash and another onto the tripod mount or the camera base tripod screwthread).
My very flexible Macro flashbracket: Studio and Lighting Technique Forum: Digital Photography Review
details the parts you would need for a RAM mount setup - if you're using the tripod mount on the camera you'd need another arm and double ball socket I would guess to get the flash into the right position, but that shouldn't be any problem to add (it provides a very firm hold that doesn't wobble or anything - as an idea Wembly also make a mount for flash units of similar design, but a much higher cost).