Brad, we up here on Central Coast of Ca. area have found that grafting in Jan till March we get the best takes. It takes longer for them to push outside because our cold weather ( at least me I'm close to Ocean) but inland my 3-miles and much warmer temps. My friend Jack Swords and I have experimented at different times of year and we have found that this time is higher percentage takes than other times of year. I think it has something to do with Dec. push of avocados new flush. I had to cut my scion wood from tree's earlier this year mid Jan. because tree's were starting to flush new growth.
I'm in Arroyo grande mesa area half way between Santa Maria and San Luis Obispo