Hello, You will get mixed answers on leaving bow strung or not, I have seen this and been told first hand, with modern glass backed bows, you can leave them strung, I myself do not do this, I unstring after use, even for the evening after hunting. I hang my bows horizontal but vertical supported by the sting is OK also.
OL Adcok has tuning on his site at www.bowmaker.net/index2.htm, or
www.arrowsbykelly.com, as for number 3. practice allot, and go to 3-D shoots, and stump shoot, that will give you an idea were you are, and what your max effective range is. Good luck, and welcome.