Last time I had this problem I bought some brass commercial/agricultural ones and tweaked them to shape with a ring spanner once fitted.
Considered that, you can buy those already angled too. The ones I have are pleasingly small though. They really suit the wheels. Bigger valves will be way too obtrusive. Not prepared to spend £60 on valves though!!
I have a while to deal with it, trying to find a part worn tyre to mock up sizes with is proving impossible!