as of the end of January or so when your cart could preview WNW's inventory, there were 12 J.1, and 114 Biffs.
There were also 4 Pfalz D.IIIa, 32 Hissos, 33 E.II/E.III Early, 41 Snipe (early), 11 Albatrilogy. Seeing how many of those are now sold out, I think the preview was pretty accurate.
from watching that cart while it was available i saw some of what i'd expect: certain kits were produced in huge quantities and others quite small, and certain types (single seaters with relatively simple rigging) sell faster.
I'd guess they made a lot of Biffs, and to some it looks complicated.
There were less than 100 early Fees, but I suspect that they sell slowly because it looks so complicated. Hope I'm right I need another one for the FE2d conversion. Already got the engine.
Oh and based on the preview, if you're looking for an Albatros B.II or AMC DH.9, you can take your time. over 1,000 of each. and when the Biff sells out, there are over 1,000 post war Biffs.
The numbers i got from this preview have guided my purchases, and I got a J.1, a Pfalsie just in time, an EII/EIII early just in time, a Snipe (still not sold out) 2 Albatrilogies (from Weta actually but the low number made me do it)... So it's worked well for me so far.
FWIW shameless hoarder that I am, these have been bought with full intent to build. I have another spreadsheet specifying how many of each type i need to build all the ships i want to build. That said, I have no problem with speculators, as long as they understand it's mere gambling and not 'investment.'
The numbers may not be 100 percent reliable as a snapshot (only 294 Dolphins, but it was only just released so I suspect they were still being manufactured, bought one anyway from the Lots-of-Models sale.
if there's any particular aircraft you want to know about or if you want to see the original sheet, ping me (or post if you think other people will want to know).