Ok I'll to resist asking but how the heck have you been able to keep your engines properly in tune with knowing what the LSN does? Sorry to take it back a few notches but have you got a grasp of the other needes such as the HSN, the idle adjustment screw and the MSN(if it has one)?

Anyway the basics are that the HSN controls maximum power & top speed; the LSN controls the idle mixture and the immediate throttle response whilst the idle adj, screw controls the idle level. Clockwise leans the needles out whilst anti-clockwise richens the needles.
You tune the HSN first then the LSN & idle last. Once you have tuned in the HSN for satisfactory top speed, the LSN is dialled in for idle mixure and throttle response. Ideally when properly in tune, the engine should accelerate smoothly from the instant you apply the throttle.
A good method to tell whether your LSN is in tune is the pinch test. Run the car up to speed, bring it in and pinch the fuel line about 1" from the engine inlet nipple until the engine cuts out. If the engine's revs increased dramatically for some seconds before cutting out then the LSN is too rich; If the engine's cuts out immediately then its too lean. What it should do is that the RPMs should increase a little before the engine cuts out after a few seconds.
Another similar method is by listening to the engine and how it settles after a WOT blip. Bring it up to running temp and with it off the ground give it a good blip of the throttle. Listen to how the engine settles and resumes idling. If the RPMs of the idle goes higher or remains high and the engine does not settle back down its an indication the LSN is too lean. If the RPMs dip and go low and bogs the engine down eventually cutting out, then its likely the LSN is too rich. Ideally after a WOT blip, the engine should settle into a normal idle until it eventually bods down after about 20 secs before cutting out. Of course this is not as easy as it sounds because it can be hard to tell whether a lean setting is raising the idle or if infact its just the idle adj. screw that needs to be turned down a smidge. The more you do it, the better you become at learning the different aspects of tuning.