The question to ask yourself is whether you want to remove the graft union now... or wait until you have more trunk growth. Once you put it on it's own roots, it will likely grow more slowly, and also might be less hardy. Since you can be very successful on most maples, you can wait until the trunk is close to the size that you want it... then do the airlayer. I've had 100% success with all cultivars that I have tried, maples root like crazy! It's keeping them growing well on their own roots that gums up the works.
The pot method works well, depending upon what you want to do. The main thing is that it stay damp but not soaking wet, whatever you use, and that you really get in there and make sure that all of the cambium is removed. If you leave cambium, it will just bridge the gap instead of making roots.
PLEASE be careful with rooting hormones! They can cause cancer in humans. Don't breath the dust, don't touch it with your bare skin.
Also, use a good strong knife. Very sharp, very clean. I used an exacto and almost took a finger off once. Now I use a Japanese grafting knife, but there are probably much better choices available. Get a blade that won't fracture when twisted, and is strong.