The key to roughing out the blank from a Tree/log is to orient the blank so you maximize the figure or maximize what the rough material has to offer.
You are not making a size, you are roughing out what finished piece is there in the rough.
The raw material will show you what the finished sized could be.
Man did that make sense?
Don't split knots, or put cracks in the blank etc.
Cut plenty of extras.
We will leave no blanks behind! (the Turning Marines)
Most bowls can be made smaller so you do the math on size
Some woods will keep there bark when dry and some won't.
For short term storage till turning, it doesn't matter. BUT, as bark dries it can come loose, so watch it for coming off during turning.
However you dry pieces, just keep an eye on them in the beginning, the first 1/2 or 2/3 stages of drying woods are the most cantankerous. Once wood is dryer than its fiber saturation point (about 30%) the drying is way more forgiving.
Be willing to throw out lessons.