A tire boot should be non-stretchy material, not a tube patch or piece of inner tube, though that would be better than nothing to get you home in an emergency. I've had dollar bills and other patches (piece of sewup works nicely) inside a tire I've ridden on for months. If I can boot the tire and not have a bulge or spread-open gap at the slit with full inflation, than I'm happy to keep riding on the tire.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72