The NH35A is the SII (seiko instruments inc) version of the 4R35,
Its a hacking and handwinding version of the 4R36, Spron 110 balance wheel. 40h power reserve -25/+35 accuracy,
You have the 4R15 which exactly the opposide and has no SII version has a Spron 510 balance wheel like the 6R15 but hacking and handwinding removed.
NH15/6 = 7S25/26
NH25 = 6R15
NH35/6 = 4R35/6