The UR3# is
Width 0.031 Thickness 0.013 TPI 15
Every 3rd tooth reversed.
I don't believe that anyone makes a blade that every third is reversed. So the comparison is tough.
Steve recommends the Pegas Modified Geometry blades. These have the bottom few reversed.
the 1R
Width .030 Thickness .0102 and TPI 13.7
the 3R
Width .0335 Thickness is .0126 and TPI 12.4
So my conclusion is that the 1R is closer to the UR#3 than the 3R based on thickness.
My go to blades are the UR and especially the #3 too. I have recently ordered a sample of each of the sizes and are going to have a "Battle of the Blades" to compare UR, the GM, and Olsen. I was originally going match by number ie #1 to # 1 but now I am not sure.
I would like to hear what other have to say too.