Actually, I mathed it out again. Where Vist 5' steps to, its 40' in the XY plane. Add in 35' of vertical (assuming the Cornugon is 10' tall, I'm aiming for the top half). According to Pythagreus, that's 40^2 + 35^2 = 2825. The square root of that is 53'.
If Vist 5' steps "up" at a diagonal, putting him 45' above the ground (allowed with Perfect Fly) gives us 40' in the XY plane and 55' vertical. Thats 68' by Pythagrean.
Vist is Caster Level 21 (16 + Archmage 2x + Orange Stone + Ring of Arcane Might + Craft Magic Tattoo). That's 5 feet/2 CLs which is 21/2*5=50 (rounded down). Plus the base of 25' gives us 75' of range. 75' > 68'...just in range!
Being an air elemental sometimes has it's perks.
EDIT: Fix't the math, forgot the Cornugon was on top of the pillar, not on the ground.