H100V might work pretty well at those temperatures. In my experience it takes real cold to cause the drastic drops in muzzle velocity that can cause point-of-impact shifts. And 90 isn't super-hot, either.
I haven't done any zero-degree tests on the Reloder powders for a while, but they would probably work OK within your range of temperatures. Of course, the only way to tell for sure is to test them, especially in your rifle!
Have you tried any of the Ramshot powders? They're the most temp-resistant double-based powders I've tried.
