Client launch: 1,200 members migrated in a weekend

Solid breakdown. The only thing I would add is to back up before making the change — better safe than sorry.

Great point. I had not considered the angle you raised in the second paragraph — it reframes the whole thing for me.

Could you say more about how you measured the result? I want to try this but I am not sure what success would look like.

Tried this on a staging copy first and it behaved exactly as described. Confident enough to roll it to production now.

This is the answer I wish I had found six months ago. Would have saved me a weekend of trial and error.

Following this thread closely. We are about to face the exact same decision and the replies here are gold.