In my case it's just a small trench so I dig the char out into buckets and inoculate that way. I am only making 7-8 buckets (about 35 gallons) of char at a time. I am going to get my neighbor to dig me a full size trench when I clear my lower property (about 3 acres) and try to get serious with it.
Anyways, another mistake I have made was trying to crush it by hand, in a square container, with one of those packer-wacker tools. Hand tamp? The results were not much better than running it over with my truck and it took forever. The truck, even on dirt, allows for more production. I have a lot of nasty land to rehab here! Really this is a scale issue and not a mistake. If you are making just a few gallons then the truck would be ridiculous but when doing it by hand, I almost gave up. Which would be the ultimate mistake.