ORIGINAL: daven
Remove the baffle.
Try both the 10x7 and the 9x7. The 9x7 should be slightly faster, but you may enjoy the flying characterics of the 10x7.
My suggestions are based on using APC props.
What he said
My only little blurb to this is is to fly that prop 10/7 for 10-15 flights. Then when you go to change to another prop, you will see the difference instantly (better or worse). Changing props every couple flights may keep you confused.