you're right, jujus have some of the hardest wood among fruit trees. Seems second only to certain persimmons(ebony). I actually recommend using grafting shears, as manual-grafting takes so much time, especially with something as hard as jujube wood. As for succesful grafts, i prefer using sugar cane as interstem, since it has this tendency to produce upright stems pretty quickly. Juju wood is generally strong and stiff, but sugarcane stems seem to be extra stiff, so even with heavy bearing of the grafts--sagging is kept to a minimum.
technically, the most ideal graft for jujus is on upright growth closest to the base, to minimize rootstoclk's tendency to leaf out. For practical purposes, grafting to upright stems 3 to 5 feet above ground is most ideal, especially if worried about boisterous dogs/cats scratching/brushing against the grafts, or rabbits nibbling on the grafts, etc. Same-caliper wedge grafts work pretty well for us, and are our preferred method. Bark grafts also have good success rates, but we only use this if we're being lazy and have plenty of thin, sub-par budwood.
same grafting options for mulbs, except that mulbs are much easier to cut and splice.
have bought"disposable" grafting shears from amazon.com at just12$, shipping included, and were pretty good, taking into account the three double-edged blades which equates to 6 blades, and may last us 3 or so years at ~200 grafts per year.
as for budwood, there are plenty of us here who actually enjoy giving them away. I typically have plenty of li budwood, and a good amount of contorted and several others, depending on local demand from las vegas friends..
actually selfish on my part. For the very reason that it makes me happy! Friends ask me why seem to go out of my way to do the legwork -- digging holes and planting/grafting those extremely long-lived trees in their yards. I end up being philosophical saying it is truly worth my while, since my time on earth is limited.
My existence is finite, but hey, i could always broadcast/plant jujus! There's just so much good about this species(health-wise, logistically, and environmentally) so a bit painful not sharing it with others..
just envisioning the likely scenario hundreds of years from now-- the great-grandkids of my friends' great grandkids harvesting from those trees i planted-- well that is enough incentive for me..