Nikon PC-E Micro - which size do I need

Using a D300 for product photography. I shoot everything from peanut size to 5 ft tools/bars etc.

If the PC Micro Nikkor will mount on a D300, due to crop factor not sure if I should get the 45mm or 85mm. Does anyone use them, would the 85mm be too long or just what I need?

I may switch to FX in the future - waiting to see what nikon comes out with next, so needs to be the right lens for both dx and fx.