Hi Ben
I've actually already addressed that in the coming update - that's long been an annoyance of mine as well.
In the full screen analyzer, I reworked curve selection to be a lot smarter. I think with anyone used to computers, it's intuitive to touch on the "unique" section of an object (a part that does not overlap anything else). So, curves will now be selected by tapping directly on them. If more than one curve encompasses the tap point, the smallest curve wins, and successive taps near the same point within 2 seconds will cycle through only those curves that contain the tap point.
It actually sounds more complicated than it is - IMO it's very intuitive, but please let me know what you think once it hits the app store - especially on iPhone, where real estate is limited. I like your screenshot, and am still probably going to do something else supplemental that would work for the main console as well - something like you suggest, or even something as simple as a small row of colored circles for each curve - the selected curve having a small white ring around it. Taps to it would present a popup where you could tap big buttons. Not sure yet - am trying to remove as much clutter as possible from the roasting console, so I'm going to defer that until at least next update.
I finished up coding the new features for the update last week, but am kind of stuck in limbo prepping it for iOS 7, and waiting for a test device. It's almost ready though.
Thanks for the feedback!
Danny