Yeah, messing around with the amp is a real time waster. Hence, the idea of downloading presets. I have now dowloaded several presets which I like.
I too found the Boss Tone Studio presets not to my liking.
Initially, when learning something new, I don't use the amp at all. I practice the piece of music until I feel competant at playing it without any amplification. Then, I use the amp to refine my playing with the motronome/drum machine and then pluging in the backing track into the Katana. This amp is very user friendly in that respect.
I will try out the link you provided.