I have an excavator for personal use, I am not a contractor. So I fill with 5g gas cans. It sucks to use them on the horizontal fill hole.
Pro tip: Convert your new style "safety" cans to properly flowing old style cans with one of these kits. So worth it.
Funny thing is, you can still buy the old spouts(just not on a gas can). Some of them are marketed as water jugs; they’re the same size, and still use fuel rated plastic. Amazon link, as example..
They can sell these because it should only be used for water cans ;)
LPT: Convert those "safety" cans to the old vented style for ~$10.
EZ-POUR Replacement Spout - Water Jug Or Gas Can Spout - Update Your Old Can https://www.amazon.com/dp/B00CYNDNM8/
Amazon has a replacement spout that is just the old-style bendy tube.