Trial and success can work for determining length of exposure in a contact printing process. Something like 30 years ago I made contact prints from 4x5 paper negatives with nothing more than a darkened room, B&W chemistry, and a 40 watt incandescent bulb. If I recall correctly, the exposure I started out with was 20 seconds or so with the bulb 4 feet above the paper negative. Doing a test print with various areas of the print receiving different amounts of exposure may make this process more efficient. http://photographytraining.tpub.com/.../14130_222.htm gives an example of how to do test strips and sheets when contact printing and enlarging.

Hope this helps you out, you really don't need lots of equipment to do contact prints of B&W negatives.