My preference would have been to fill it with the stuff they did my 2 front tractor tires with. I had to have them sent to a place in PA, and it was about $125 a tire to fill, but, guess what, no flats in 3 years!
I am sorry to report there is a "dent" in the tire. Not sure if it simply was having the weight of the wood on it, or I used it to soon and did not let it cure long enough. It still rides better then when it is out of air. If I had it to do again, I would have had one air escape hole and as soon as I saw foam coming out I would have made sure it was well sealed and not lose the rigidness of the expanding foam!