Prop- measure from the hole to the blade tip. Double that number to get the diameter.

Charging- Depends on the battery. Some manufacturers rate their lipos for more than a 1c charge, while others don't.

Disposal- You have 2 choices, the right way and the fun way. The right way is to discharge the battery completely using first your charger then a low current draw such as a small lightbulb. Then soak it in saltwater for 2 weeks and dump it in the trash. The fun way is to stab it with a screwdriver on a flame safe surface and watch it go off like a Roman candle. Then toss the charred remains in water for a day or two and throw it away.

Storage- 40-50% is pretty standard for storage. It's helpful if you are not going to use them for a month or two.