im also new to the banshee, and had a ton of problems getting it to idle, hard to start, bogging, etc
i found this link helped me out
http://www.dfn.com/agservices/jetfaq.html
my problem ended up being the tors,out of adjustment floats, one plugged pilot jet,and the float bowls on the wrong carbs, left to right are different, now it is running great,but i also had to adjust the
air/fuel screws and sync the carbs
i'm no expert with banshee's but it sounds to me that your bogging off throttle is your pilot circuit to rich, i think a 30 is too big, try the stock 25 or 27.5. and try to get your quad warm and set
your air/fuel screws when idling,fully seat the screws,not supper tight, then turn each one out,i did mine in half turns,until you get a good crisp throttle response without a bog or hesitation.
mine is 1 1/2 turns out
check out the link though