You want to graft around mid February to beginning of March in Florida.
The best time is before the annonas push their Spring growth.
This is tricky because the two cold days Dec 24th and Dec 25th caused
some of my annonas to push after the 80F days. Then we had 2 nights with frost
and Winter isn't over. If you do graft and a cold front comes through I would
protect the grafts and bring them in.
As Galatians522 stated cherimoya is the preferred rootstock or maybe even better would
be to graft onto African Pride seedlings. Sometimes you have to use what you have this season
and prepare better for next season
