Update- seems like getting into another big (5 or 10lb) setup is going to cost me acquiring another tank to fill or get swapped.

On the tubing I've got (and linked to before) it seems like the sodastream-sode terminal might actually just be this:

Stainless Steel Adapter For CO2 Paintball Tanks Can Be Use On Soda Beverage Machine Save Money On Refills. https://www.amazon.com/dp/B01G62DJOO/ref=cm_sw_r_cp_api_i_vFTNFb3M6P9NN

It unscrews from the tube setup so it's a single piece of adapter I'm going to do some more research today and possibly pick up a paintballing tank. I'll let you know go this turns out.