Amp+rack = space needed above it?

[Jamesemt]

I'm about to rack my gear (including a Superfly head) - is it better to leave a 1u gap directly above it, or isn't it needed?

Could also do with some advice on the order. I have a 2u Preamp,Superfly head and a 1/2u wireless system. Thinking of adding a tuner at a later date too.
What would be the best way of stacking/sorting them? I'm new to this rack lark

[mr pablo]

If its a 6u rack then i would go,

Tuner at the top (1u)
wireless (half a u)
pre amp (2u)
then the superfly on the bottom(2u)

[alexclaber]

If your amp has vents in the top or bottom it probably needs clear space there. Most well designed rack gear does not need clear space in either direction.

Alex