Spent the last day or so reviewing all the previous posts on the use
of inert gases for top-up, and wine transfer.

I understand the caveats that Tom S raised about a false sense of
security.

So after all this I would still like to use either Nitrogen or Argon
for the temporary protection it provides.

However, I am not sure exactly what I need, and how to best use it. I
want to use it for temporarily protecting partially filled carboys,
displacing oxygen in bottles at bottling time, and for protecting
unfinished bottles of wine (like Private Reserve does). So I know I
need:

1. A tank - 20 or 40 seems to be physically the right size but I have
no idea how long it would last
2. A regulator - I believe the same regulator (and tank) could be used
for Argon or Nitrogen. Question is, what specs for the regulator?
Seems that you want a low pressure output to minimize wine
disturbance.
3. Nozzle? Gun? - So how do I apply it to the wine? I've read to do it
gently to not disturb the wine but not sure what fitting I need or how
to best do it. Given that I also want to use this for unfinished wine
bottles, it needs to fit that application as well.
4. How do I use it as part of the bottling process? How much gas do I
need to add to a bottle, and how do I control it?

Any additional insight appreciated.
Dan