I think the large stones that everyone is flushing come from the liver which has 2 large main bile ducts (as well as lots of tiny little ones). The gallbladder duct is only average 5mm so I don't believe your stone could pass through. The soft waxy stones that everyone is passing don't show up on ultrasound/xray, the hard glass-like calcified ones do. I have many calcified stones in my gallbladder. I have flushed many times over the years and never had a stone get stuck (but I've also never passed a calcified stone although my health has RADICALLY improved). Liver Flushes have never caused gallbladder attacks for me. The Liver Flushing controls my gallbladder attacks and I hardly get any now. When I do, they are extremely mild and pass in 20 minutes, less if I drink warm water with a teaspoon of Epsom Salts and lie down.
Check out http://www.sensiblehealth.com/. you may need to take the Chinese herb: Gold Coin Grass. Someone else on this forum had a 2.7cm stone. He's been taking GCG for 6 months and it has shrunk to 2.3cm I think. Ok, it's slow but at least it's shrinking!
If you really focus on detoxing, improving your diet and you feel good when you liver flush, you shouldn't have a problem. You said the stone is in the GB neck. Is it loose or stuck? I would go very gradually. But please avoid having your gallbladder removed AT ALL COSTS!! Don't give up!