Spoke length or how to true wheels?
nyb seems to run same size hub shell as nankai, so i did say 184mm ~ 186mm depending on cross lacing pattern and rims- if is in-line or cross-over.
truing wheels: you seriously need a truing stand. evenly tighten your spokes by eye-balling the spoke threads is not very accurate as i 've seen spokes' threads vary by as much as 5mm in length. You might get lateral( side-to-side) within 1mm, but you will never get the dishing( centre line) and radial ( up&down) inaccuracies by that method.
I've seen a Canadian-based pro level rider asked on this forum why when he flip the front wheel, the rim will rub against the brake pad, while its fine other way around- that's dishing for you. Even the park tool professional truing stand needs to be trued on a yearly basis with a aluminium wishbone guide that cost $100++; most shops can't even be bothered with that.