When I was trying with the first camera I made I was using Ilford RC multigrade paper. Now I am using Tetenal RC Variable contrast (which I guess means the same as multigrade). I don't know why but I like better Ilford than Tetenal.
I've had good luck with Ilford MGIV VC and Adorama brand VC paper. I think your camera has a flat "film plane" so some people might recommend glossy for better contact prints. I have not tried that myself so can't comment.
There is a choice between VC and graded paper too. I've only tried VC.
I think there was another thread on APUG recently about this.