That' seems like a pretty good way to get the bars up and a little forward. I had the street slammers which have the same rise and pullback but because I'm tall the pullback got a little uncomfortable after a while. However, Heritage bars are much different from drag bars because your hands are up higher. Just keep in mind that changing bars or bar position is totally for what fits you. If you do change the risers, I highly recommend you change the riser bushings to polyurethane bushings. Stock bushings wear out pretty fast and since you have the bars off, they're right there.
You will have to change cables, though. The rule of thumb that I was told was 2" is all the cables will comfortably move. After that, you'll want to change them. I'm looking at the 08' catalog right now and it looks like you can get cables 4" longer. I don't see black ones though, I only see stainless or the Diamondback cables. If you want black cables, Harley introduced the Diamondblack cables for the 09' catalog which your dealer will have. Good luck and if you change the risers, let us know how they work out!!