It is hard to tell in a carbureted engine. Running at peak is certainly OK at 7000ft and you can start leaning in the cruise at any altitude. Without an engine monitor and fuel-injected engine you are flying blind.
As long as your CHTs are fine and the engine is smooth, you should be OK. Do you have a VP prop?
It all comes down to the fuel-air ratio in each individual cylinder. If one cylinder is richer than another it will produce slightly more power, giving some kind of roughness. On the rich side of peak EGT, the power curve is much flatter, while on the lean side of peak, it drops off quite a bit.
Read John Deakin's articles on the subject, there is no better teacher than him. Search for "Pelican's Perch #" numbers 63 to 66.