One issue I wondered about is that graft height or budding height does not change as the plant grows taller.
Basically the graft union stays at the same original height.
Grafting on very small seedlings, could mean that the graft line is going to be at 2 or 3 cm for the life of the plant.
There is a preference for higher graft heights overall 20 cm for orchard trees for protection from fungal disease.
On the other hand, I have read that Japanese Citrus is budded quite low to reduce suckering.
I find it more difficult to work low on a plant, so often bud higher, also for size matching and ease of taping.