Personally, I put it on kill and hope for the best! If you haven't done a big wheelie before, don't be concerned. You can gauge that your are going straight by looking straight ahead. I tend to look to the left a little, around the A-pillar. And of course if your really skewed up, you'll see a wall! You'll have more problems ironing out wheelie bar adjustments than you will learning to just ride it out. The problems arise when the driver suddenly lets off the gar and there goes all the nice parts in front of the firewall.
Just let it all hang out, dude! (see how old I am?).
My 3 favorite runs in my life are 1) my first big wheelie and 2&3) catching third gear still in the air and not touching the asphalt with the front tires until almost half way through third. Oh, what a ride!!!
