Updated 1st post to be more accurate of what the difficulty level is.
Except I find sob extraordinarily hard, sometimes
This would be an error in my naming. If I named SoM Normal, and SoB Hard, it might make more sense for you. I'm willing to rename the ranks if you provide an appropriate naming system.
With this ranking system, jumping up one rank isn't just a little bit harder, it's much harder. SoB is 2 ranks higher than SoM.
Spells/spy operations in the same rank are roughly equal in difficulty.
This version still has errors in it. . .(done on purpose)
SoE & SoQP should actually be in the somewhat easy category. . . but I wanted to show that they are slightly more difficult than SoB. . .
edit: I'll move them back to the somewhat easy category, but note that those two are slightly harder than the three spy operations above them.