I know this guy that makes pots here too, we go waaaay back ;)
 
Q, You need not worry about the "dangers" of boil off.  Nitrogen is already 80% of the air you breath (if I remember my High School science class).  I did crack a window just because I had my little bencher with me (who is starting to walk btw).
 
One of the things I like with LN2 more then DICE is when u drop the DICE in the pot, you get potential splashing from your acetone.  That can mess up any lines nearby over time, or just erode your plasti-dip parts in close proximity.  If you spill LN2 on it, it will just evaporate into nothing, which it can land on your mobo (which I really don't think is a bad thing?). 
 
It is going to cost you quite a bit to fill that joker, but it will last you a weekend I am sure.  PLUS your dispenser is probably considerably more efficient then mine so who knows how long it will last you??
 
I do like DICE just for the simplicity of it, and its much cheaper then the LN2.  I tend to get my feet wet with DICE first, then play with LN2 after I max out the DICE potential.

How much in Jersey to fill 50L Nate?  Where do you go?

i went to a place locally, and he gave me a deal simply because he underestimated how big that 50L dewar is.   I am sure you will too, oOnce you get the box that is taller then your kids ;)  He just rang it up as a "large" dewar which he thought would be about 25-30L.
 
I think it was somewhere in the $60's but he honored the "large" price over the phone, but when I brought it in he almost died.  He made a "new product code" in his computer in case I brought it back and he was going to sell me more LN2. 
 
Might take some pictures of a project I have been working on for the past 2 days.  Sorry its not copper, but its the next best thing...

Was he just a local guy, or a big franchise like airgas?
 
Copper price have got to be going through the roof in this economy.....
 
Pretty soon you'll be making things out of tin, like they did with pennies in WWII.

HA!   I will just have to suck up the additional costs of the copper.  He was a local guy, not a franchise

 
Hmm, i wonder what it could be?
 

 
Oh, it's my prize from the Scavenger Hunt! But the box is far too small to be a DAS box...
 
Well me and Shane were emailing, and i present to you guys, my new Scavenger Hunt prize! 
 

Sweeeet!  Sold out of DAS boxes?

IDK what exactly, but Shane said Promise had been slow working with them, and since it has been so long since the scavenger hunt, he offered me a gtx480, the next thing up in value that he could get me immediately.

 Welcome home Nate.
Any of you guys want 2 evga bucks via affiliate code?
The first one (someone I know) PM me they're code gets it.

pm'd.  Whatcha get awalleye?