Best use of pity?

I currently have 199 pity for void shards, and was wondering about the best way to use this. I have already saved up some voids so I can basically pull a legendary whenever I want. My current plan is to wait for a 15x progressive event for a very high value void legendary, just for that extra chance to ensure getting a good one since they are so rare. Is this the best course of action, or not worth the potentially long wait? Would it be more worth just getting the guaranteed legendary during a champion chase? If not, which champions would you consider waiting for?

For extra info, I am not doing the current fusion, and this would be my second void legendary from shards.