Maybe it's a little bit overkill, but I purchased an extra OEM funnel (like the one stored with the jack), as it works best to hold the fuel fill door and get past the anti-syphon flab as well. Then, I have a standard filler funnel like this one
https://www.autozone.com/shop-and-garage-tools/funnel/flotool-blue-multi-purpose-funnel/71065_0_0?
that I then install into the OEM funnel after the OEM funnel is in the fill spout, then it works perfectly.
When I tried to use my funnel by itself it seemed that it didn't hold the flaps well enough and I got gurgling that caused some spillage around the gas filler.