First, there is no "midrange" screw. There's an idle screw and a HS needle. Set the HS needle first. Then, put a short piece of fuel tubing on the fuel inlet. With the idle needle closed, blow into the tubing while holding the carb throat to your ear. Open the idle screw slowly. When you can JUST hear air blowing through, you'll be within 1/8 turn either way of right.

Are you sure you got it reassembled correctly?

Be SURE the idle bar is where it was, using the screw head marks as a guideline.

Silicone? Outside or inside? Why?

Dr.1