There are more 'color's to teh 400's than I was aware of until recently.
I personally don't need a 400n, if I could get a few of the 'odd' colors.........but expect them to be out of reach.
Now there are semi-flex nibs, and maxi-semi-flex nibs in the 400's....'50-65 era.
There are 15 degree grinds in the Obliques...........I do have a 30 degree OBBB (Eyeball not marked because of the rolled gold piston cap, 500 mine of which is tortoise.
I have in 15 and 30 degree obliques in a mix of semi&maxi, in OBB, OB, OM & OF..............pure luck.
I don't have any of them in Pelikan in 30 degree grinds.
So what do you want the nib to do??? I think that more important than picking 400/400n/or 400nn.
There are some very nice colors....6-8 colors. Every time I go looking at someones Pelikan Com....I make sure I play the numbers.
Tortoise or not, light or dark, or sea green, some reddish...and that's '50's not the post 97 ones.
But if you want a 400n....good luck, Rick has one to sell..... I did give getting one a try...but knowing it was rare never expected to even give getting one a try....but was very happy with the late model light tortoise 400.
German vintage '50-70 semi-flex stubs and those in oblique give the real thing in On Demand line variation. Modern Oblique is a waste of money for a shadow of line variation. Being too lazy to Hunt for affordable vintage oblique pens, lets you 'hunt' for line variation instead of having it.
www.nibs.com/blog/nibster-writes/nibs-germany Info on Bock nibs
The cheapest lessons are from those who learned expensive lessons. Ignorance is best for learning expensive lessons.