Is it "Dinguses" or "Dingi"?

The burning question that has haunted humanity since the dawn of time... (or at least me since last Saturday):

The plural of dingus, is it "dinguses" or "dingi"?

Let me use it in a few sentences:

* I would push my shopping trolley through the aisle, but I'm blocked in by a couple of dinguses/dingi.

* It's a 3-lane highway, and we have three geriatric dinguses/dingi driving under the speed limit blocking the entire road.

* Why is it all these dinguses/dingi have to use change on the bus instead of a travel card?

* The drive-thru at Macka's is continually full of dinguses/dingi.

* All these dinguses/dingi bitch about the price of fuel, yet they won't give up their 2.5 tonne 10mpg SUV's.

* Each year, 1000's of dinguses/dingi trip over their own clumsy feet leading to astronomical public liability insurance costs.

* It took Channel-10 eight long years to cancel Big Brother, thanks to all the moronic dinguses/dingi who watch it.

* I wish you dinguses/dingi would leave some comments.

If I'm not mistaken, dingus is from the Latin. So one would expect the correct plural to be "dingi". But there are many counter examples in English where this rule does not apply, so perhaps it is "dinguses". Indeed Firefox spell check flags "dinguses" as the correct one; but I don't know. (It also flags "color" and "aluminum" as correct, godammit.)

Can someone help me? In the meantime, I'll just have to reword the sentences such that I don't need to use the plural.

* I wish I had a dollar for every dingus I had to stop myself punching in the face, I'd be a rich man.