wow, i have never had a flat tire on ony of my bikes.
do you have the rubber liners inside the rims to protect the spokes from rubbing on the tubes?
liners are the way to go because they are cheap and easy to install.
the green slime stuff is ok, but if you ever need to deflate the inner tube to put on a new tire, the green slime will clog up the valve stem and make it very hard to get the tube flat enough to get the tire off the rim.