I forgot to use the 'strength' option when quantizing my midi track, so it was set at 100% and is perfectly quantized sounding a bit too unnatural.  How can I now take this and randomly make the notes slightly offset?

Use the Quantize MIDI plug-in and adjust the randomize parameter. This is a non-destructive process so to make it permanent, select the clip and choose Process > Apply Effect > MIDI Effects. 
 
That's not your only option. Depending on the clip size you can convert it into a step sequence. The Step Sequencer has numerous humanization possibilities...it's very cool. You can then convert the sequence back to the PRV if you want.

It just dawned on me why so many midi files I download , when you look at them in piano view are all over the map on the grid. I assumed the dude didn't know how to quantize so I apply it and the song always sounds better ( to me)  afterwards.. But it might be the song was quantized  but then messed with on purpose : ?  
 
 
 

Cactus Music
It just dawned on me why so many midi files I download , when you look at them in piano view are all over the map on the grid. I assumed the dude didn't know how to quantize so I apply it and the song always sounds better ( to me)  afterwards.. But it might be the song was quantized  but then messed with on purpose : ?  
 
 
 

guilty of thinking that as well.