You certainly can try other options. Once you leave the security of RTF systems though it's very wise to get a wattmeter, learn how to use it, then you get proper answers to your questions.
Too small a prop > lacks power (may be more efficient though)
Too large > maybe burn something up.
Over propping is very common. Folks think they are getting more for nothing. Pretty much they are producing heat, running their batteries down faster, and feeling good about it.
So, there's a range that will work well. You need to stay inside that range and from there pick a prop that you feel works best for the plane and you.