u8"\N{OHM SIGN}" is probably the closer to right thing, since it's distinguishable from u8"\N{GREEK CAPITAL LETTER OMEGA}"
Distinguishable yes, but canonically equivalent, and discouraged.
The ohm
sign is canonically equivalent to the capital omega, and normalization would remove any
distinction. Its use is therefore discouraged in favor of capital omega.
I'd missed the discouraged part. Is that also the case for Angstrom, I hope?
Either way, spelling it out will avoid confusion, and probably should have a Note so that someone else doesn't make the same mistake I just did.