Yes this is correct. But I would paint it on with a brush, don't try and airbrush it on. Liquitex clear sealer is the one to use, make sure its a flexi one because they do rigid ones too.
I used liquitex gloss medium on mine and yes definitely brush it on i rushed mine on and it fogged up in certain areas make sure to take your time
Dont mis-understand me here. I said paint on latex base coat. Don't attempt to paint on gloss sealer after you done detailed airbrush work, you will take it straight off! You should airbrush sealer, you could thin it slightley but it should be airbrushed on.