lean is a relative term.... its not good to be lean on any needle.

what I mean by a lean LSN would be it can idle till the cows come home with no change in RPM and revs up without needing to be "cleaned out" BUT the HSN will need to be ran on the rich side (another relative term) to prevent overheating and or flaming. This tuneup gives the best runtime and "touch" power in my experience. But some engines dont like this tuneup, so there's more variables than can be typed here. Anytime someone brings their engine to me locally to tune I always start with the clean and lean bottom ad see how the engine likes it.... if it doesnt ill go the other direction. Rich LSN's can easily be spotted by a varying idle speed after full temp is reached. I run my engines with both tunes depending on the track etc etc

I plan on doing a few vids on youtube to clearly show the differences, its very easy to spot the differences once you see them.