Custom Nendoroid Hair

Hi! I ordered parts to make myself a custom nendroid and pretty much everything should be easy to modify but Il have to make custom hair. I ordered a base that's "bald" enough because the hair is pretty darn specefic to the character. On the bright side it's also short apart from a handful of tuffs of hair that poke out from the bangs, I'm researching for good clays that harden without the need of an oven. I own air dry clay but I'm afraid it'll crumble and not be very durable, I'm considering milliput/just getting a higher quality air dry clay. Do you guys have any recommendations? Preferably something that won't cost an arm and a leg.

➡️TLDR: doing modifications to nendoroid hair. Need something durable that hardens by itself (no oven) and affordable.