Congrats on the job...6th and 7th graders, too! You must have ALOT of patience:)
I use the New Image lock and roll for two reasons...the flange is the only one that works on my "peaks and valleys" tummy and the filter! I find that the only time it might fill up with a little air is when I am either laying down on the couch or sleeping...but, as soon as I get up, either burp it (no locking tabs) or empty, it starts to work again! No need for the stickers in the shower, too!! I wish all the manufacturers would figure that out, no one should have to do the sticker thing!
I don't know about cutting the flange down, but it is skin color and more "cloth like" than the others I've tried...I don't even worry about what hangs out over the lower rise jeans since it isn't too obvious.