Realistically there's only one exam that perfectly simulates what you're going to get on Step 2 CK. That's the Step 2 CK.
Instead of looking for a single pre-test to tell you what you're going to get, you ought to be looking at the trends. UW Self-Assessment has some notoriety for underestimating scores, but the predictive value of where you'll most likely land depends a lot on other tests you do over time. If I had to hazard a guess without even knowing you, I'd probably say you're just somewhere in between 205 and 220.