Thought you where going to talk about a variety of lime I was unfamiliar with. Still I read with amusement. I agree stranger things have happened, but I will say the rootone is unnecessary. The wound reaction of the cambium layer is what knits the scion to the stock plant. When I was in college I had a very good horticulture professor who's father used to field graft seedlings in the orchard. The main thing he used to stress was to make sure the cuts are done with a sharp knife and the scion is cut smoothly without any undulation so there are no gaps for air to get in and dry out the scion as it heals. Also, try for semi hardwood scion wood preferably pencil thickness or slightly smaller. Semi Hardwood comes from the center of the branch. Greenwood=at the terminal end is too flimsy and Hardwood at the base of the brach=too hard and thick. Prep the scion wood by defoliating at the petiole. The axillary buds on the branch are located where the petiole of the leaf attaches to the stem. Also called "nodes". I like scion wood with at least 2 to 3 nodes so when the scion sprouts there is the potential for more leaf and stem mass. Use budding rubber or rubber bands of medium width approx 1/4 inch and as long as possible. If your using rubberband cut them to form one strand. Or I have had luck with green non adhesive tie tape. Wrap the graft tight to make sure there is good contact between the scion and the stock. Start the wrap below the graft so you have an area that has stability and continue over the union of the stock and scion. Like your bandaging your knee if you injured it. Tie off the end by pulling the terminal end under the final wrap and cinch it tight and cut off the excess if need be. You could add grafting wax over the wrap if you think air is likely to get in. Also use some type of pruning sealer at the terminal end of the scion becuse that has been cut too and can dry out as well. Or perhaps you could bubble gum like you tried already. The book to consult is the "Grafter's Handbook" which is still in print, I think. It's been around a long time but is still the text to consult as a primer. Try the American Horticultural Society website; they have a bookstore. A little long winded but I tried to make it concise. Look up whip grafts or vaneer grafts. I like those. Good luck!!!

Finger lime seeds do not grow true to type. You will probably get a tree that will never fruit if the seeds even germinate at all. Your best bet would be cuttings.

I purchased a whole tree from just fruits and exotics it’s doing well

I like to take the seeds from the fruit and put them directly into my potting mix, with only a quick rinse to remove sugars from the fruit; if I can't do that, I rinse them and put them in a ziplock at the bottom rear of the refri with only a slight touch of chloro to retard mold. Seeds stored like that will still be good up to a month.