I wanted to update this with some findings that may be useful to other people. A month or so ago I did some grafts on an in ground tree and on several seedlings. Its gotten quite hot here but the scions have done fine in full sun. Just parafilm and clips on the grafts was used. After 2-3 weeks the clip are removed. Temps have hit 90 several times and no issues, grafts are still taking. I also did a bunch of seedling trees and intentionally left them in full sun. The grafts are taking no problem in strong spring sun. And small new growth also unaffected. So don't be afraid of sun when temps are under 90, it seems to be a non issue.
I had really good luck taking scions off of trees about to do their first good flush for the year. Around mid march seems to be a great time to take scions with swollen buds. I would say March is the best month to do grafting here. Even with some buds being flower buds, doesnt matter.
There will be extra grafted sharwil trees in a month or so if anyone wants any of those. Im really impressed with the way sharwil is growing here and am planting more of them here. Havent tried the fruit yet but by all account they are excellent.
Heres some not so great pics of the grafts