Setting up a "new" 2005 Rock'

OK, my bike is a 2005 with 3421 miles on it, stock except for OEM front and rear dresser bars and windscreen. I am a new rider. I don't even know what to look for in how my bike handles. I'm 6'6" and weigh 280lbs.

1. What should my rears be set at? If I am reading them correctly they are set at 3.

2. I find the bike a little bit low for me, I will probably find a taller seat or pad my stocker to give me another 1-1.5 inches. Any suggestions on taller seats?

3. So I raise the seat rather than the whole bike right? Lower CoG is better right? Or will a slightly taller bike enable more lean in the corners?

You can do it with the seat and longer rear shocks, risers to get the handlebars up as well if you're not all legs.