Pull off the air filter from the carb and you will see the carb slide in and out as you pull the throttle and release while looking down the carb neck.
You should have about a 1mm gap when your finger is off the trigger or braking. When you pull the trigger to full throttle, the carb should be fully opened. Use the trim settings on your transmitter to make sure it fully opens. Don't over do it. The slide barrel only need to get to the edge of the carb neck.
The boot will expand and contract while the carb barrel slides in and out.
I am not sure what you are asking. Hopefully this helps.