http://www4.ncsu.edu/~clrivard/TubeG...gTechnique.pdf
I'm not sure if this link has already been posted to this site, but I'll do so here to be sure. I found this a useful read, particularly with statements like the following, which gave me a target for temp/humidity in the healing chamber:
"Make sure humidity, light, and temperature
levels inside the chamber are constant before beginning
the grafting procedure so that the grafts
will be placed into a well-functioning chamber.
As noted above, the relative humidity level
should be high—between 80 and 95 percent,
and the temperature should be a constant 70 to
80oF. Use black plastic to block all available sunlight
from entering the chamber until the leaves
of the newly grafted transplants attain normal
turgor levels—until they no longer show signs
of moisture stress.and the temperature should be a constant 70 to
80oF. Use black plastic to block all available sunlight
from entering the chamber until the leaves
of the newly grafted transplants attain normal
turgor levels—until they no longer show signs
of moisture stress."
BTW, last night I grafted my first three seedlings (Wes, Cherokee Purple, and Costoluto Gen.)
Good luck.
-naysen