[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXK184&P=7]Here are the 1/16" wheel collars.[/link] They do stabilize the bird once it's airborn.

You can make the T-gear longer, but keep in mind the longer the gear is the more it will resonate or vibrate. This will make the bird shake more in flight. It can help at the very beginning, but at some point you will probably want to shorten them again.

Good Luck and Welcome!