EFI or not. Woodgas or not. What has worked well for getting the engine started, running; moved into shop/enclosed buildings parking; emergency get-you-home back-up is a small stubbed in gasoline carburetor.
Dutch John ended up tri-fueling his was-alreadty-converted-to propane Chevy big-block pickup.
His gasoline carburetor was a small Solex?(German) side draft carburetor cut-in/out isolated by a big 1/4 turn ball valve.
Nope you will not get good cylinder to cylinder A/F mixture supplied. You will not get full engine power capability.
But it will start and run with enough power, rain or shine/sub-zero freezing weather.
And that part of it can be see-do mechanical carburetor simple.
'Course to many a gasoline mechanical carburetor is mystery-weird-science too.
As long as they are float types I do OK. Diaphragm pumper types drive me nuts too!
tree-farmer Steve unruh