Best rate in the Global is achieved somewhere around max turb penetration speed but I hardly ever do that. I recently climbed to FL450 in 19 mins. Vfto is more likely to be best L/D than min drag but the engines dont produce maximum power at 160-190 kts. Even when you are OEI you still may get a better rate at a higher speed because he remaining engine produces a bit more power and you use less rudder so there is less drag. There are no climb figures for it, however, because here is no reason for a manufacturer to certify it. I am a current Glex and 6000 training captain and have flown the aircraft all over the world. I have had plenty of time to sit and look at the AFM and CCM and am pretty up to speed with what a 50 tonne swept wing jet aircraft can do. But hey, if you want to climb your global at Vfto, go for it....