The main advantage of doing a small amount of tibial lengthening like 3 cm is it means there's almost no distraction phase (1 month maybe), and then you're just waiting for consolidation. There won't be any ballerina foot. There won't be any major stretching/tearing pain. No major physio except exercising to regain strength and the minimally lost flexibility. It's simple, quick (relatively), and easy.
Lastly, as part of a comprehensive approach, you can retain your biomechanics almost perfectly. I'm thinking about doing around 3-3.5 cm tibias with 4.5-5 cm femurs to get total 3+" in two stages in almost perfect proportion. Again, this should also avoid major stretching/tearing problems.
Problem is mostly time related. Hard to get that much off work.