Vic a trick in air layering is to let the cut dry a bit. This can be done several ways. As you mentioned, torching. This is not as drastic as it may seem. It is not like you are charring wood but more of lightly passing the flame over the cut band. This in turn drys the cut and will help with callous development which is critical in the development of new roots. Another technique used is the use of alcohol which will dry the the cut. Not quite a fast nor drastically as a flame but it is effective for easily rooted trees. The last is the old school way and that is to let your cut dry for a day or so to promote the beginning of a callous. To be honest, I have used this technique successfully, but don't like it. I guess its psychological. Knowing that my tree is sitting open and bare to the world...makes me fidget
