Any advice? Which Swablu do I evolve?

I don’t yet have an Altaria but I two decent swablus.

A) CP297 Shadow Swablu (13/13/15) Ranked 36 in Ultra League

B) CP390 Regular Swablu (13/15/14) Ranked 14 in Ultra League

I only have 517 candies and I’m looking to evolve one for Ultra League / Raids. I understand I’ve got a few options here.

If I purify the shadow one it will be a Hundo, but won’t be shadow anymore.

Any advice would be greatly appreciated.

Many thanks.