Regarding steam.. Although I haven't baked in a while I never remember having a problem with steam. Usually the oven was full though. On the times when I would just do test batches I would add steam by partially filling an old tuna can that I had poked holes in (very tiny) and placed it in the corner of the oven. This worked very well, the tiny holes allowed the water to drain very slow and produced quite a bit of steam. I had to play with it for a while to get just the right level which was just about covering the "ribs" on the bottom of the can..I don't know how it would work for the pizza ovens but I imagine it should be the same. I think I got the Idea from an oven I saw that had a cast Iron disk in the hearth floor about that size that was above a water source..it dripped onto the disk and made instant steam. I have also heard of people just putting in an ice cube right on the hearth bricks...
Now that I think about it I guess I really never had a problem with steam because most of my recipes are very high hydration and I really don't know "exactly" what hearth temps I was working with because I went all out and decided that if I'm gonna bake Old World Breads I'm not gonna use a temp gage

I used a combination of the arm (mmm I can smell the hair burning now

) and the cornmeal method. Next oven will have thermal couples, it was a great experience learning to do it that way but..really whats the point... People can talk about burning cookies in the oven (conventional ) or a roast but you have never REALLY burnt something till you have burnt it in a brick oven..am I right guys???