Meditation and brainwaves questions

Ok. So meditation is ultimately about producing certain brainwave states. I've heard that producing Gamma and Theta and Alpha waves are all good. However, most meditation exercises don't tell you which state you are producing. I think this is an important step that's overlooked. Mostly they say just clear your mind (which I can sometimes do) or visualize (which I am terrible at). Maybe I should just focus on doing the exercises and not worry/think about which brainwave states I'm producing. But I feel that the brainwave state I'm producing is ultimately what the meditation is all about. So, I either have to get an EEG to tell me what brainwave state I'm producing (expensive) OR, I have to know which exercises are producing which states. So would breathing meditation be producing theta waves? Would visualization meditation be producing alpha waves? And how important are these answers to my meditation practice?

Learn to Meditate - Brain Wave Meditation

"Researchers at the University of Wisconsin working with Tibetan Buddhist monks have shown that the meditative state of the monks produces high-frequency gamma waves and brain synchrony, or coordination."

I wish there were a more comprehensive guide to meditation that explained which exercises produced which brain states and not just the simple instructions that say follow your breathing, count to 10, be compassionate, etc.

There are different types of meditation. The meditation is the goal, not any specific brainwave patterns.