I would consider it a waste to use a guaranteed lucky trade on a low level Cranidos. You will eventually catch weatherboosted Cranidos near or above level 30 that take significantly less candy to power up.
Another issue is whether it's worth using it on Cranidos at all. I would much rather get a good legendary, because Cranidos could very well become common in some future event, which makes getting a lucky much easier. Lucky legendaries are never going to be easy to get unless they lift the once per day trade limit.
tl;dr I think you shouldn't.