I made it out 26,689 ft with my Mavic Pro battery mod (2x MS 3000mah Lihv - Side Mount), ItElite Nano Sync Antenna Mod. I was in the desert mountains and had some elevation to contend with, by the time I hit 5 miles I was 1100 feet above my takeoff and was still less than 400 feet from the ground. There is nothing out there but desert and a concrete plant so the signal is pretty awesome. I was flying in gps mode at 31mph out and back. I returned and landed with 35% battery left so I think I will try a 6 mile run next! I have included my airdata link below. @JakeMaxxUAV
Airdata UAV - Flight Data Analysis for Drones
Those dual 3000 lihv are good for over 40,000 ft on a good day. 35,000 no problem for you.