Just to follow up, I did my own too and it turned out really well....
To check the valves being closed I pulled the valve cover off and watched the cam lobes. I turned the engine over (mine's an automatic) with a socket and ratchet on the crank pulley nut.
I also bought the factory wand, which you hook to a shop vac to suck all the particles - both the blast media and the carbon knocked loose - out as you blast. I did take my car up to school where I had a pretty much unlimited supply of dry compressed air, but it didn't take that much, I think I could have easily done it at home with my little compressor.
The results were pretty amazing, they basically looked like new when I was done.
