I FINALLY have order confirmation on this instrument and hopefully will have it here within a week or two.
I still don't have an answer on H2, so am going to stick with He for now.
In the interim, though, I thought anyone coming across this in a Google search might be interested to know that Agilent does still stock and sell the filaments for this instrument. They were a bear to find, and I probably wouldn't have dug them up if Ron at SIS hadn't given me the P/N-it's 9300000400. https://www.agilent.com/store/productDe ... 9300000400
As I write this, they're a whopping $311 each, which means that once I have a stockpile of good filament bodies SIS will definitely be getting my business to rebuild them rather than replace outright.
Also, Ron at SIS advised that the single most problematic part on them seemed to be the source cartridge heaters, and advised that they can supply a replacement. Old threads on this site indicate that this has been a problem since these instruments were new and current.
Otherwise, though, I'm actually really happy to go with this for a QQQ. Among other things, AFAIK all have CI, which to me is a big selling point on a QQQ and is an option that will add ~$50K to an Agilent or Thermo instrument. Also, Thermo likes touting their vacuum interlock for source cleaning, but these instruments have that also(all have it-it's not an extra-cost option like on Thermo instruments). I'm not totally clear on this, but it seems to me as though the same interlock that allows you to clean or change the source without venting would also allow column swaps.