Okay, by going through NoME line by line I think I can piece the Finweans back together.
Relevant sources, from newest to oldest:
Silvan Elves & Elvish: 8496 SY in Aman.
Shibboleth: Miriel lived until Feanor was grown; Galadriel is older than the Silmarils.
NoME 1.XVIII: Elves grow at 3SY per "year" until 24, then 144SY per "year" after. Mortal equivalent age is age in "years"*0.75. Mortal age 36 (=48 "years") was a typical age of first child in "troubled times".
NoME 1.XVII.3(7): Elves had children at regular intervals.
NoME 1.XVII.3(6): In Valinor, elves married later and had children at wider intervals than before the March.
NoME 1.XVII.3(1): After the March the age of marriage increased towards 48 "years". Usual age in Valinor was 36.
The key point here is that the 48 years in XVII.3(1) is the same figure as in XVIII. Therefore, the 36 in XVII.3(1) can be carried through as well - it translates to an age at marriage of 1800 SY.
From that point, I played with interval lengths. AAm has Turgon and Finrod born in the same year, which felt like something Tolkien would have kept; the coincidence of Aredhel and Galadriel's births, however, is broken by the stuff about Galadriel's youth in XVIII. To get Finrod and Turgon born in the same year, I had to say Finwe's children were born twice as fast as their own kids; that actually fits with AAm, once you add the girls in. I settled on an interval of 3.5VY for Finwe's children, and 7VY for the next generation, because it put Galadriel in the right place (she comes out as 20.5 "mortal equivalent" at the Exile, which is nice.)
Where it
does still break down is the generation after: Idril is older than Galadriel, and Orodreth and Celebrimbor wind up born after the Exile, which, no. But it comes pretty close to a workable scheme!
(I've kept the AAm spacing of events at the start and end of the Aman years: the Silmarils are still only around for about 400 SY before the Trees die. I feel like Tolkien would have deliberately kept the "rapidly-developing catastrophe" vibe the lengthened timeline gives.)
hS