For really top performance it's always worth trying all possible waxes and manufacturers, but since I'm out of racing things, I stick only with Swix for kick waxes. For glide on xc I still use whatever works best for certain conditions based on this what I figured out during all the tests I did in past. But for kick I would say Swix works good enough that you don't need to worry.
I have no idea about VP line (I'm still fully on my beloved fluoro racing service only VR hard waxes and KR klisters, even though klisters I'm slowly changing to KN and KX, as I'm running out of KR klisters. But based on what I saw, I would say also VP line would work very similar to VR waxes. Ranges are same/similar so VP45 is pretty much same as VR45 for example. As for "holes in lineup", on hint... if VP45 works same/similar as VR45, then that's coldest wax you need. Forget anything colder (VP40 & VP30, or VR40/VR30 for old lineup), as they have no better glide and no better kick then VR45, even if temperatures are way under -5c. It's same thing from old "blue extra" days, when old blue extra was coldest wax you needed, and it went same way at least until VR45. But as I said, no experience yet with VP45 or other VP waxes.
