Steve,
   I was taught in the military to go about 45 degrees nose up before
starting the roll in a barrel roll.  The nose should then be on the horizon
inverted 90 degrees off heading, then completing the roll at about 45
degrees nose down as you bring the nose back up.  Doing this will allow
positive G's throughout the manuver (picture Bob Hoover pouring a glass of
water in the barrel roills he did in his Shrike).  If you start the roll
from a much lower deck angle, you're going to have to apply some negative
G's while inverted to keep from scooping the nose out.
   I haven't had the itch to try this in my ES.  As Chuck Yeager would say,
"I don't recommend it, but it can be done".  It should be a snap in your
plane!
   Skip Slater