First time using this service and had some concerns initially but it all went well.
- Going from Diamond to Predator takes roughly 3~7 days depending on your play schedule vs theirs and ultimately a bit of luck
- Booster will appear offline and you can request what characters to play though going into Predator they may need to use their main to consistently get points
- You can leave 2FA on and accept their initial login, this allows them to play but can also be a safety net if you are concerned.
- Ultimately i'm pretty happy it all worked out.