You can do wonderful stuff with paper negatives. Nearly ortho response, no red. And if you use multicontrast paper instead of graded, it gets even more confusing.
If you haven't already purchased the paper I would suggest using some #2 grade RC paper (Freestyle Arista.Edu.Ultra for example). Or what you might have on hand. If you are going to use multigrade, consider fitting a #8 yellow filter to the INSIDE of the camera. This helps cut down a bit on the wild contrast swings you get with MG paper. Inside because if it is outside, you get to focus all the crud stuck to the filter!
Since paper is cheap it is easy to do some personal EI tests. Start with ISO 2 and do a progression 2,4,6,8,10,12. If you are using sheet film holders, you can easily get two tests per sheet. Then either contact print or scan to find your personal EI. You might also want to do an EI test for both "Sunny-16" conditions and open-shade conditions if you are using multigrade (blue light sensitivity).
Or, just say screw it and slap in a sheet, call it ISO 8 and take some shots!
Not much reciprocity failure in paper as film until you get past a minute or two exposures.