In my infinite wisdom (which means none), when I had JGS make my first reamer, I had them make it at 1' 45" thinking why not split the difference and see what happens since I planned to shoot Lapua and Eley. Most theories at the time had Lapua better at 1' 30" and Eley at 2'. As Tony says, other than making me feel good that it says 1' 45" on the print, I have no idea what it is. It seems to shoot just fine. I suspect the bigger factor using a reamer is concentricity to the bore when used and how the chamber is finished after using it than half a degree of lead.
The only way I would be confident I was getting a true 2 degree is with a CNC and a boring bar. I would think even with a manual lathe and boring bar the margin of error could have you well on both sides of it at that degree.