Set them wherever the engine runs the best.

Seriously, I assume you're talking about initial setup for starting. Set the idle needle so the head is just about flush with the throttle arm. Open the main valve 3 turns, this will provide a nice rich mixture for break in. You will tune the needles later, but for initial starting that's fine. Or you could just go to the Super Tigre website and download the manual, which will tell you the idle needle is set just fine from the factory and not to touch it untill you get the top end set.

Andy