I actually GMed off of frenzied ostards from 98.9 in one afternoon looking for a savage ostard (that I never found at the time). It went surprisingly quickly considering they were all first time tames - not sure if it was pure luck or what but I was pleased.
It really doesn't matter if they are first tames or not. As long as you don't have a 100% chance to tame something, your chance to gain is probably the same. Re-tames "gain better" because they increase the amount of failures you have, and you still gain on failures. This means it requires the same number of tame attempts, but less actual animals since each one can produce more gain.