If you want to see plenty of detail in the contact print the general advice is to print at no more than grade 2 and keep exposure to a minimum commensurate with still having detail. Some may look a little grey and flat but give you a good idea of which you want to print full sized.

If you can be sure that all or at least most of your negs will all print at a certain correct grade then contact printing at that grade with an exposure that reproduces a miniture frame as you'd want the final print to be is worth trying.

If you haven't got it, I'd get Tim Rudman's book " The Photographer's Master Printing Course. He has some useful things to say about contact printing. Oh and just a few more things about the whole gamut of printing.