Hey Mike, you will LOVE unicycling, everyone does! (I'm glad I inspired you to get one, that's cool!) I am pictured using a 24" in the pic, but my filming unicycle of choice is a 29". (as i am riding in the manhattan clip) if i have a lot of time to get up and riding without the need for too much control when filming, i will use my 36" wheel. (i would use the 36" on a ski hill, for example)
the general rule of thumb: the smaller the wheel, the easier it will be for low speed control. the bigger the wheel, the harder it will be at low speed control, but the more momentum you can gain and easier to roll over things like bumps and curbs. When filming, the larger the wheel also means the less your knees will move up and down shaking up the footage....not so bad with a camera stabiliser, but somthing that needs to be considered nonetheless.
if you spend an hour a day on it, you should probably be wobbling happily after 10 hours. do yourself a favour and don't try to lean on walls to learn...learning by freemounting will give you all the skills you need by the time you are riding. everyone can ride, it's simply trial and error. you can think of it like this...try to get on unicycle. drop unicycle 500 times. now you can ride.