The extra service time is far more valuable.
I am inclined to give the plan another year. I don't want to see the potential RotY candidates up until late August, after there's too few days left to lose rookie status. Something like 40 or 45 days or 130 ABs.
As for Gallo, I think you play him to see if you can trade him. You'll be likely to get something more than the equivalent of a pick at the end of the 1st. I'd consider a Herz quality guy to be worth more than the bonus pick, and a decent year from Gallo can get you that. I've spoken about my infatuation with a "heavy" outfield with Thomas or Gallo in center, the other in a corner, and Garrett in the last spot. Free Winker to DH, and use Joey at 1st. If Yepez earns a spot, fine. That's your pop line up.