I also have a pinscher and I think that the 2.2 raceking would fit on the rear. I think you should try putting your 2.2 on the rear to check clearance and if it does fit, get a 2.2. I weighed both of them and the 2.0 is 423g and the 2.2 is 479g. The 2.0 is absolutely tiny. It's way narrower than the 1.95 sb8 and for the 56g difference between the 2.0 and 2.2, I would much rather have a 2.2. Just my Opinion.
Thats interesting, i didn't think about about how small it would be but thats true smb 8's are a lot bigger then regular tires so maybe I should just go with another 2.2 i'll have to check and see if it fits then.