3 months and 90-100% Primal along with your pre-season training will help you lose a shitload of fat. I would think you could be easily under 300lbs by end of March.
Do not over-train (as an athlete you probably understand this) and don't over-think it. You are making a huge step in the right direction just by trying Primal and trying to tweak it to perfection right out of the gate will only result in you getting frustrated quickly.
People too weak to follow their own dreams will always try to discourage others.