Priming 1 gallon in 1 gallon mini keg

[nyrmc23]

I'm about to prime a one-gallon batch in a 1 gallon mini keg for the first time to not have to bottle. Two questions:
1. How much priming sugar should I use?
2. How much head space should I leave?

Thanks!

 

[VikeMan]

I'm about to prime a one-gallon batch in a 1 gallon mini keg for the first time to not have to bottle. Two questions:
1. How much priming sugar should I use?

I'd recommend using a calculator, like this one:
https://www.brewersfriend.com/beer-priming-calculator/

2. How much head space should I leave?

In a keg? Well, if you have the beer, leave as little head space as possible (but make sure to clear the gas dip tube). But, if you want a similar level of carbonation in the beer as you would get when bottling (with the same amount of sugar), leave about 4-5% of the total volume as headspace.