I noticed it recovers 2% per tick, but I was not sure what the interval is. Also, when adding physicist buff (10% each) does it increase the speed of recovery (faster tick?) or just the raw value then recovery is 2% of that ? I do not recall being able to find that information anywhere.

2% every 2 minutes
Grid surge is the same as using a shield amp on your ship.
Still 2 minutes but the 2% is from your buffed shield value.

Thanks. I knew it was more than 1 minute