I am not a develper and it shows, I am a sys engineer and build infrastructure so this was a large part of not knowing. I also think a small part was the fact i was using Daybreak with some Easing of cyber controls so it worked a bit more than a standard model. As for the model change i learned rthe hard way never to do this, and you are right i dont know if it was the OP50/51 rounds or the model that caused the issue, but apples endpoint security part was the ultiimate block. I could have taken a different direction and not used the enpoint piece of it but i would have lost the past 2 weeks of work and would have had to start over, in in a session that ran for a total of 14+ Days of actual agent work, would have been a nightmare.

That 14-day session is the strongest argument for checkpoints. Since the Apple endpoint-security piece was the real blocker, a short written decision log at each phase boundary (what changed, why, what the exit criterion was) would let you retrace whether the model switch or the extra rounds drove the growth, and make it cheaper to branch off without losing the two weeks of work. Pinning the model for the length of a campaign and changing it only at a boundary is also a simple way to keep the comparison clean next time.