kegging with nitrogen

I am going to purchase a nitrogen tank. Is a 5lb tank efficient enough, or should I go with 20lbs? I want it to last at least a month, I am not a huge stout drinker when I do drink it, I want it to be served on beer gas.

My second question is, at what PSI should I be serving on? I know it's according to temperature but if someone could give me a general number I can figure it out. I plan on force carbonating it with C02 (2vols) before I hook it up to the beer gas. After I hook it up to the beer gas, how long do I have to wait to serve it?


Any input is much appreciated!


cheers!

The size of the tank is going to have to be up to you.  I would look at the price difference and if it isn't much between a 5lb & 20lb and if you have room for the 20lb, go with the 20lb. 

I have my beer gas set to 30psi.  Once your keg as been force carb you can serve right away.  All the beer gas is doing is pushing the beer out like CO2 would do but with a mixer of nitrogen and carbon dioxide which gives you that nice waterfall effect.

Were you planning on buying the tank and having it filled, or paying a deposit at a gas supplier and doing exchanges?

The latter is much more convenient.  Also, you can start with a five pound tank and see how long it lasts. If you decide to upgrade, all you have to do is pay the difference on the deposit on your next exchange.

Keep in mind though that when you exchange, there's no guarantee that the tank will look nice. Sometimes I get a polished aluminum tank, and sometimes a heavy, dull, steel thing.  But that doesn't bother me.

My experience is with CO2, not N, but I'm sure the process is the same.