Kadie,
With the Cleft or "V" grafts that I have done. I like to not use too long a branch and I have snipped some of the leaves off if there are many on the branch, otherwise I snip the top 2/3rds of each leaf off. I have started leaving the terminal growth tip with out snipping.
What I did this last time was choose which branch I going to use and snip off any leaves (if needed) prior to doing the grafting for a day. I wanted the cuts to heal up before doing my grafts?
I used a plastic film that is similar to Saran Wrapfor food. Doubled. Wrapped it tightly around Union.
When I make the "V" cut on the scion portion, I also slice the skin off on the sides of the Bottom of the V. About here " -V- ".
Told that most times this does not work is if the scion is not pushed into rootstock V firmly enough. Then wrap.
I place a baggy over the whole upper portion of plant and tie around the trunk.
I think the only thing to watch for is too much condensation build up in baggy.
Rick