Nitrogen bottle and an air tank

What size reserve tank are you guys using in your nitrogen setups?
ive got a 5ga. tank but space is limited and im wondering if i could get away with running a 3ga. pancake tank to fit in the spare tire well in the trunk.
ive been told the nitro will keep the tank filled almost as fast as you can use it but i havent tried it yet so im lookin for answers.

as long as your bottle has psi to push itll keep your tank fullbecause its constantly pushing whatever you have the regulater set

You really dont even need a reseve tank. A dually i just rebuilt had the nitrogen line run directly to a T with the valves on it. Ran that way for years.

yeah i dont use a reserve. my regulator chatters sometimes but im used to it.

I have 2 3 gal tanks on mine and ran nitrogen for a while. When I bought my Viair 480s  I didn't see the need in the nitrogen so I got rid of the bottle. But your 5 gal tank will work fine. I never thought about doing like the guys above did and not even use a tank, just a spliter. That's a good way to save space, I mainly used my nitrogen because at the time the compressors I had sucked! I get to switch happy and run through a big bottle every few days. haha