Personally, I say if you want to pass when you're not on T, don't go for longer cuts. They can make cis guys get misgendered here and there so it's not really the best way to go. There's still some shorter cuts that aren't buzzcut. You can leave it longer on top and just get a shorter cut at the side for example, like the pics thatboyfresh posted. It's hard to tell someone what cut to get because it's best for an individual to decide what they actually like. Just try not to go too short too fast. That way it gives you something to play with if you feel it doesn't work.
Another thing. If you have a wave in your hair, it really is best to go short or at the very least straighten it right out! Even if it's natural it looks more girly because girls will use product and blow drying to get that look. I have a natural wave in my hair and I freakin hate it! When it was longer I straightened it into an Asian type style like a shorter Stephen Chow style, but I only had this because my parents insisted on longer hair. So I could leave it as is and it looked girly, or straighten it and at least have a chance at passing as male. But I pretty much always passed with short hair. With the Asian style it was 50/50.
My brothers have the same sort of hair. When the older of the two was younger and grew it out he hated it because people misgendered him. But after puberty he's worn his hair both longer and short and gets away with it long because of his voice and facial hair that he didn't have pre-puberty.
