I have to agree with dorasdaddy, my first choice would be a Cake Walk Supreme (www.hedgehogwheel.com), then a homemade bucket wheel, and then I have to say the Flying Saucer, but that's only because I only have experience with these three wheels. I haven't used anything else because I don't feel anything else is really worth it (when you have these already).
I have 4 CWS and they are great easy to clean and super silent best wheel out IMO.
I also have a FS it is easy to clean as well and is quite..comes in 2nd IMO
I have a few Giant Comfort Wheels not as easy to clean and very loud but got em for $12 each not bad for the price.
I wouldn't put even a baby on a 6" wheel. It is too small. Also, why bother keeping something that is going to me know good. He will be fine without a wheel for a week or two until you can find a proper sized one.
Thank you Lillysmommy! I was trying to find answers without postin, but no one seemed yo be saying sizes! I am picking up a 6 week old girl this weekend! Very excited and very nervous to have my first Hedgie!