The big patches are for big tubes. Love to find a source for bulk small ones. For small leaks, I keep the tube pumped up to sand, apply the adhesive and then the patch. Then I let the air out to put pressure on the patch with some small, smooth object. That way, the tube isn't overstretched when inflated in the tire, nor are the edges of the patch under stress. Can't do that for large holes, but they're infrequent.