This is the same guava tree.
Left and center are bark graft.
Right is side graft.
All grafts used water bags.
Most important step is to cut the nurse leaf.
The capillaries in the cut end draw water up to the scion, to keep the scion fresh.
I used 3 bags to graft a big branch of Atemoya.
I left grafted tree under shade.
I didn’t know it got morning and afternoon sun light.
All leaves except the 3 inside water bag wilted.
All 3 water bags were dried.
So check water bag and use a syringe to refill.
If you have good shade you could graft a big branch, with a few water bags.
My friend have successes using 1 water bag to graft 12” Atemoya branch.