Help with compact 30/32mm Alpha Choice (2 Viewers)

[tenex]

how little pincushioning will suffice (and whether it's uniform or more complex),

I realize that I'm not certain exactly what "[more] uniform" would mean here, in contrast to the variation in Swarovision etc. Does a classic design like those decades ago involve a simple (linear?) gradual increase of pincushioning toward the field edge, or... ?

 

[Binocollector]

Does a classic design like those decades ago involve a simple (linear?) gradual increase of pincushioning toward the field edge, or... ?

Just comparing different old EWA porros seems to suggest that they do indeed have a gradual increase towards the edge unlike the Kowa BDII for instance, which has a moustache-distortion.
But there are also older EWA binos that have it, like the Komz 6x24 which has a very similar distortion to the Kowa BDII 6.5x32 -- Russian binos in general seem to have less pincushioning than Japanese ones but all the old Tento-models from 7x35 up to 20x60 have a rather narrow FoV anyway. The Komz models are wider but have less pincushioning than the Japanese binos.
But as far as I can tell -- all the Japanese wide angles from the 70's or thereabouts have a very uniform increase towards the edge. Which makes their panning behaviour much more civilized compared to something like a Kowa BDII -- unless you pan up and down a lot which makes the edges of the FoV bend upwards and downwards. But from side to side -- they are really nice. It seems there is always some compromise involved.