I will be playing a round this coming Thursday, late in the day so it won't be busy. I like the suggestion of dropping a ball at the 150 marker and hitting my 7 iron from there for the practice and distance data. I spent some time at the range today, mostly because I got a new FW (Adams Tight Lies, 16 deg) and was hitting my irons a lot more consistently.
I think when I originally started this thread, I was flustered because the range I had gone to the previous few times, you are hitting off a cliff and it's really hard to tell how far a ball actually went. Today at a different range that is nice and flat, it was much easier to see, at least up to 150 yards. I'm still consistently carrying around 160 yards with my 6 iron, which is about where I was with my old clubs. I think I'll play the new ones like I played the old ones. I think I'm also trying to break some bad habits I learned swinging the old clubs, since the lie angle wasn't right for a guy as tall as me. These new Mizunos are a much better fit, but my position at address is different than it's been since the lie angle is different. I think it will take some getting used to but be better for me in the long run.
On a somewhat side note, the new Adams FW is pretty easy to hit! Plays more like an iron, which is exactly how they advertise it. I was happy with the distance I was getting from it as well as well. The FW that I had before was my hardest club to hit, but this one has a much more compact head and was easy to hit.