Well, I think now is indeed a good time for a supply run (or other investigative/preparatory activities) - we've reached out to the girls and it seems we now must wait for them to reach back.
Reviewing the description on OP of commerce down here, particularly in Nightside, it is colorfully explicit to the effect that one can by ANYTHING down here....
Well, aside from various accessories, I am after high-rated plastique.
Rating starts at 6 and goes up to 25 (if you can afford it).
Technically, it all has the same high Availability Rating, but thought I'd check with the GM before we go there and I buy up their entire stock of military grade explosives....