Yes you could bud now. If you're in a very hot area, you may want to wait until the nights cool off a bit, but citrus really can be budded nearly any time. If you plan to T-bud, it will need to be when the rootstock is actively growing, so the bark will "slip" easily.

As for budwood sources, not only do you not want Florida wood, realize it is against Federal and California state law to bring in budwood from ANY other state or country, except under permit (which is not easy to get; mainly universities or USDA centers with strict quarantine facilities). So your source will need to be from within California. If you go with UCR, the big advantage is that their wood has all been virus-indexed, and so they can tell you whether or not a certain variety has any viruses, and if so, which ones. If you just get wood from the favorite tree of a neighbor or friend, that may also be just fine, but in that case you will not know if or which virus(es) it may have. On some rootstocks that may be ok. But on sour orange, if a scion has CTV, it will cause the tree to decline. On Poncirus or any of the citranges, exocortis will cause them to be stunted. And various other rootstocks have various susceptibilities. That's always especially a danger if you're making a "fruit cocktail" tree, in that, for each new cultivar you add to the mix, you raise the probability that one or more viruses will be present.

Spend the $. The quality and variety of UCR budwood is amazing. If you are a novice at budding you very well may need 12 buds. I know I did.

Took me 18 buds to get two Sudachi grafts to take.

Have you been successful grafting citrus trees in the past, or are you still learning how to graft? You might start off by buying a Tarocco orange tree, and practicing your bark grafting technique using scions from it. When you are satisfied with your success rate, then start with the expensive rare bud wood, like the University of Riverside. One Tarocco orange tree isnÂt enough anyway.They're wonderful!
When the University of Riverside says 12 buds, they mean just that, three little sticks with around six to eight buds on each.
IÂm new to grafting and was finally able to successfully graft apple trees this year, cleft grafting. All my plum and apricot grafts failed, all the bud grafts. UofR sent six good sized twigs for grafting July 3, three Tarocco nucellar orange twigs and three Red Valencia orange twigs. The Bream Tarocco twigs were put on a Quarantine Hold, not shipped. I cleft and bark grafted most of them. So far, none of the twigs have sprouted out, and the six twigs I bark grafted all look dried up and dead. Yes, grafting is easy. But the teacher at one of the grafting classes I attended said it takes lots of practice to get it right.