If you have a name that is unfamiliar to most, then you will get asked how to spell is or people will spell it phonically. That is different from having a name that is usually spelled one way, which you then choose to spell differently. That is just a real pain in the ass for anyone who has to go through life with that name.
So, I'd go with either Aaron or Lucas - both nice enough names, but I'd never give a child a well known name, spelled in a different way.