Adding subtle tempo changes

I am working on a project which contains EZKeys and Addictive Drums 2. Before adding audio, I'd like to add random small variations in tempo, so instead of it the project being a strict 100bpm throughout, there's a degree of humanising. I know how to do this within AD2, but how would you do it at project level? I'm particularly aiming to make EZKeys sound less mechanical.

Thanks!

I would recommend enabling snap at no less than a 1/4 so you don't generate hundreds of unecessary tempo changes - maybe even just at measures.  Too sudden changes within a measure will just make the timing sound 'wonky' rather than human. Humans tend to speed up or slow down gradually over several measures or going into and out of choruses/bridges - unless the piece is really intended to be rubato, in which case it wouldn't usually have drums.
 
If the piano part was entered in the PRV rather than recorded as a live performance, 'humanizing' velocities and durations will probably be more important than varying the tempo.

I do that all the time in Tempo view. Very simple when everything is MIDI.
 
What I would really love is the possibility of using a CC (like Mod Wheel) to alter tempo and record the changes in real time as the music flows. Pretty like a conductor would do in frot of an orchestra. Don't know how complex that would be to program.