I leave mine connected all the time but some people disconnect. You'll have to temporarily reconnect the gas when you pour a beer. You need to replace the volume of beer with CO2 otherwise it will come out of solution in the beer and your beer will become flat over time
A search will find you some tables that tell you what psi to carbonate at for a given temperature and % of dissolved CO2.
So determine the carbonation required for the style of beer and the temperature you want to serve it at then set your CO2 regulator at the given pressure and you fridge at...
I'm in Cardiff. It's raining here. The red warning for wind is 3am to 11am tomorrow.
parkrun cancelled and Cardiff's game at home to Watford postponed.
So I get a lie in and won't have to suffer an afternoon of crap football.
I don't know how many CO2 bulbs you would use, but it would work.
Other options are a soda stream cylinder or a 5l mini keg with the CO2 bulbs, which is what I use.