100 % iv Milotic go for lv 40?

I wouldn't, the second week feebas was out I put 64 rare candy to evolve my level 35...in the meantime evolved another feebas, then hatched enough to give me 328 additional feebas candy. I run 10k eggs in my infinite, so I'm not an egg factory either. I rarely use my two Milotic.

If it were me. I would not invest rare candy. I'd walk it and hatch more eggs to get Feebas candies. Some people here would tell you to not take it to level 40, but I would. I'd just be patient in getting the candies and not use rare candies.

As an attacker, Milotic is comparable to Vaporeon and outclassed by Gyarados (not to mention a certain legendary). Its main use is as a defender with Dragon Tail + Blizzard. Unless Milotic is your favourite species, I would advise against spending Rare Candy on it. Catch more, hatch more and buddy walk (remember that you cannot put your buddy in a gym).

Rare candy? No.

Take the patient approach and power it up over time.

Hell yeah I powered up three!

All hatches

I shamelessly poured a lot of rare candies to max the first one. Had a mountain by the next two.