Casey,
Sometimes, despite doing everything right, your old boss will still burn the bridge from his side. This is also a possibility. Some people don't take employees leaving well.
Having said that, if you are a senior (and I assume you are since you are leaving to start your own firm), I would give a minimum of a month's notice. This give your current boss a chance to start looking for a replacement, transition, tidy up loose ends, etc. In some cases, you may be asked to stay a bit longer to finish a job, or what have you.
Basically, treat your boss the same way you want your future employees to treat you when they leave to start their own shop.
Oh, congrats!
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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