If it was me I'd probably aim for as many pumps as baby would normally have in that time. And I'd do one side per pumping session
I'd do what you feel comfortable doing in terms of out and about etc. In terms of no of feeds, pump as many times as your baby would feed and if they usually feed on only 1 side or both sides per feed x
I exclusively pump, I just do it wherever I am. Mine isn’t noisy though. It’s an elvie stride , just stick in your bra and go. Have to do 1 side then swap to other as I have only a single pump too. Depends where I am whether I swap it in public or go to the toilets to swap sides lol. I can generally do it kinda under my top so people can’t see