Huy, my comments were just about veitchii being able to be grown as an intermediate. Lowland variants are not extreme lowlanders, and the highland variants are found at more intermediate altitudes, so both "lowland" and "highland" veitchii can be grown as intermediates. I've found the lowland species less forgiving of cool temps than the highland one is of warm temps. Neither variant is fast growing, but the lowland variant, in my conditions at least, is slower than the highland one.
Intermediate conditions are around 25 - 30 degrees centigrade during the day, and around 17 - 22 C at night.
Hamish