5 centimeters is acceptable, 6 centimeters is slightly excessive, and 7 centimeters seems unfavorable in my opinion.
Are you considering one or two surgical procedures? In my view, if you also intend to undergo femur limb lengthening, it would be more aesthetically pleasing to only elongate the tibia by 5 centimeters.
The only concern I have is that even in the initial state, your arms appear short.