Brought pet auto buff. . .

However, if it's true there might be some delay in the gem's recasting, I'd rather just do it myself.

If it's anything like the auto-buff system KMS had when i played tespia, i can personally say it recasts ~2-4 seconds after the old buff disappearing. So if you wanted to use it for MG or something like that which needs to be up the instant it's gone, it's not really a great idea.