"Would a 3-6months be realistic timeframe for this?"

How many mercury fillings did you have? When were they removed?
I had 25 of them! I felt better after chelating for a month or two, then felt much worse. For those like me who had many mercury fillings for many years, chelation could take a few years. Many feel better after some chelation, and then they might feel worse as deeply stored mercury starts getting dragged out.

Don't chelate too aggressive as you could crash and feel much worse. With chelation, slow and steady is what works.