As i understand your original message, you are currently interested primarily interested in producing salt prints from your in -camera negatives. I have been making such prints for several years and have made them from every conceivable type of negative including a paper negative from the 1840's. in an attempt to help you achieve at least a modicum of success right away I offer the following. A densitometer is not necessary, but good visual observation will help fine tune your process.

1. I use only Ilford FP4+ because it is the best current film for building contrast.
2. I expose it at an EI of 100 in order to have very thin shadow density.
3. My development times have been carefully calculated for the developers I use. I suggest that you start with your current developer of choice. HC 110 dilution "A" is a good choice. If you happen to be using this developer ow at Dilution"B", just use "A" at your current times for "B"
4. Double you normal development times if you are using other developers.

Your goal is a negative with shadow detail barely visible, and Highlights through which it is difficult to read a newspaper in normal reading light.
These methods will get you in the ball park and you will need to fine tune them for optimal prints. In the prints you are looking for open shadows and good white highlights.

Good luck.

Jim