As far as understanding the measurements, If memory serves me correctly I believe Tyll posted some primers on his measurement techniques back when he first started up inner-fidelity. I bet with a little searching you'll have no trouble finding them.
Once you read them, it helps to start going through his reviews and try to see if you can match up his subjective impressions with the objective measurements. Once you've looked at enough of Tyll's reviews you start to get a feel for how the measurements influence his subjective impressions. Eventually you'll be able to look at the measurements and intuitively guess how the headphones are going to sound.
Tyll can comment here, but in reading his reviews I can't really remember any occasion where his impressions haven't been borne by the measurements.
As far as what conclusions I draw, I know I hear things somewhat similarly to Tyll so between the measurements and his subjective impressions I feel like I can get a pretty good idea for how the headphone is going to sound relative to the gear I've had and heard.