I can't address your specific questions as to installation, as I've not installed one.
Is your SW pulley a new one? IIRC, some of the older front pulleys had issues that were finally addressed with a new design, last year maybe.
I did have a ton of problems with belt squeal when I first took possession of my 900, new from the dealer with stock pulleys. So, the fact that you're now running an SW pulley may not be the issue. The dealer goofed around with me/it for a month or so, until the left side of the belt had been chewed up so badly that the belt had to be replaced. That happened within a few hundred miles, so you want to make sure that you're not doing the same thing. Drive belts are rather expensive to replace.
My assumption would be that the belt is probably too tight and/or the pulleys are not properly aligned. I assume that you don't have a belt tension tool, so if you want to adjust it yourself, you'll have to do the hit or miss method, not loosening the belt too much at any given time.
hope that helps
2010 Vulcan 900 Classic LT