Many growers do it a bit differently. Here is what I do.
Grow out a seedling in a red Solo cup. It’s time to transplant when the seedling’s leaves extend beyond the edges of the cup. A decent root system will be in place by this time.
Pot up to a 10" gardening pot. I’ll grow a plant out for about 2 weeks in this pot.
I then transplant to a 10 gallon pot as my last and final transplant.
Very few do this. Most of us water to ~15% runoff and leave it at that. I just eyeball my waterings. If I’m off by a half-gallon, then it’s no big deal.
Yes, once the plant is capable of taking a watering to runoff. A good measure of this is whether or not the plant can consume such a watering in 2 to 4 days. Seedlings should only be given a few ml of water at a time. Watering quantity can increase over time as the plant grows larger.
Not necessarily. There are a few things that can cause browned leaf tips, excess nitrogen probably being the most common cause.
Remember that overwatering is not too much at 1 time, but too often. Water and then let the pot dry out before watering again. Cannabis withstands dry soil very well. Some wait for their plant to wilt slightly before watering again.