How much nitrogen will i need?

[UncontrollableEvil]

I'm going to be doing this nitrogen with the bag and hose thing soon but as I've never purchased nitrogen I am not sure how much to get? I know looking into it I can get a tank at a welding supplies store. Also, will I need to get anything with the tank? Or is it simple as get a hose over whatever nozzle and open the valve part way? I just want to make sure I dont have to make multiple trips or become handicapped by failing to have enough during the attempt. Thanks everyone .

 

[kerolox]

https://sanctioned-suicide.net/threads/inert-gas-cylinder-regulator-general-refresher-summary.30657/