I know someone already posted a video somewhere
but I have been using the scooterwest gas funnel for the last few fill ups on my GTS and Sprint.
I am a decent filler upper of Vespas but these CA gas pump nozzles are a challenge, not only do they have the snorkel but most don't let you regulate gas pressure delivery much.
With the funnel I can put the nozzle all the way in and let the gas rip full speed until the nozzle automatically shuts off and still get a full fill up.
I bought 2 so far, I gave the first one away to a new Vespa owner.
Only minor issue is a minuscule amount of gas is left on the funnel.