I've read of different methods for airlayering. One of course is wrapping
the wound in sphagnum moss, then the moss ball in clear plastic sheeting. I
have also read of securing a 4" pot (or slightly bigger) around the moss
ball and leaving it open.

It seems the disadvantage of the open pot would be the rate at which it
would dry out, but it seems it would also give easier access to watering.
Concerning the plastic wrap, someone on the list once suggested that the
closed clear plastic wrap could result in much greater internal heat during
the hottest days, resulting in "parboiled maple." The open pot would seem
to allow excess heat to dissipate...(?)

Any recommendations on each of these methods?

Also, I've received conflicting advice about the timing of airlayering A.
plamatum. One one side, I was told to wait until late spring, when the
leaves had sufficiently hardened off; on the other side, if you wait much
past early spring it will be too hot. It is June in Houston, temps are in
the 90s and I have 4 months of growing season left. Can I airlayer today?

Thanks!
Blake in Houston