i'd keep it stock, unless you really want to start messing with it... one thing will lead to another. Honda builds a really well engineered machine right out of the box.
If you want to start tinkering, your going to have to start learning and stuff. Alot people start off tinkering and then wish they'd just kept it stock. It's a slippery slope.
But tinkering is kinda why alot of us are here.
My 2 cents.
But yeah, bottom it out and then find whatever the how many turns it is out (counter clockwise) from bottom... what ever the stock position is. I'm not sure what the stock position is...
Ask for stock position, I mean the rotational position the fuel/air is in now, which I assume should have been set from factory since the dealer stated they don't touch that.
But are you stating that leaving it as, "lean" which was proclaimed Honda does for emissions, is good if you want the best out of the standard carb, air filter, and exhaust? Or are you saying the risk of making a bit richer is not worth it if you are not expert.