Seriously,
If your stoppers are leaking get a larger one, to stem that leak,
Stoppers with ribbs are the go
If your stopper balls gone AWOL
Put an extra pump into kite to allow for small loss of air when placing in stopper,
If you carnt handle this terrible scenario
Then go to your local kite shop, give them your gear and ask them to fix it for you
Whilst your at home google the top 10 countries for innovative people
You'll see we're down the ladder