Argon

[MartinS]

...but if I were to start inflating my dry suit with argon, I assume the only way to do this is to buy a first stage (with as few ports as possible) and then connect the LP port to the suit. Just feels like the unit would become quite bulky, especially with an A-clamp first stage (can you have DIN on a 1.5L cylinder?) Not thinking of going there yet, but as i was wondering, thought one (or more) of you guys and gals may be able to shed some light on the subject.
Cheers

[Dominic]

Unless you're diving mix, Argon isn't really going to make much difference to your warmth.
A comparison of thermal conductions:
Air        100
Helium     586        
Argon       68        
CO2         54        
You can see why people with helium in the mix don't want to put it in their drysuits (plus it costs too much to waste there) but when you're on air or nitrox, it's really not that significant.
But getting back to the question: You're pretty much right, but you ALSO need either a DV or an OPV (Over-pressure valve) as well as a direct feed - if you get a freeflow develop, you want something to bleed off the pressure rather than your first warning being the hose exploding!
You can put a DIN connection on any cylinder, the size makes no difference to the valve.