I am strictly a 1-legged jumper, and this is because I am not much of a weight lifter and I am very skinny. I can dunk easily off of 1 leg but I come nowhere near off of 2 legs. Here are some of my 1-legged dunks:
When it comes to 2-legged jumps, the highest I can get is high enough to get all my fingers over the rim and hang on it. I want to be a 2-legged jumper because that will improve my rebounding and 2-legged jumpers seem to have more control in the air when going for the lay-up. I have a weight room available to me if necessary, I just need to know what to do.