Instead of putting on a riser why dont you buy the telescoping handlebars, The work awesome and the run right around the 180 to 200 mark. They are great for the trails as well as the powder slam them down or up or find just the right spot for you. There have been quiet a few guys around here who have put them on. Guys from 5'10" to 6'5". Ask around but these will be perfect for you.IMO:d
The telescopic bars are not for everyone. I found them too sloppy and when you raise them up, they actually put you farther back on the machine. I actually took mine off and use a stock bar with a 3.5" ROX riser and a relocator plate to move the bars forward about 1". This setup works great for me.