1) Not sure it'll really make a difference. Winter may make it rub a bit on your jumper or something but not totally sure.
2)No experience sorry
3) Forearms can be practical, depending on where on the arm. The closer to the elbow the easier it is to hide if you want to. Pain wise, I reckon if you get it on the boney bit of your arm its gonna hurt way more than like the flat of the arm.
THIS is a handy chart
4) Not gonna suggest an idea simply because I believe that if you don't come up with the idea yourself, you're not committing. So I avoid giving ideas and critiquing tbh,
Best of luck!