how big a riser can I use?

I bought a stock 2008 Dyna Superglide last year for a bar hopper. I like it all right, except I want the handlebars closer to me. Anybody know how tall a riser I can use on the stock wiring harness and cables before I have to change them? There is some slack in the wiring and cables, but I'd like to not have to buy 2 or 3 sets of risers before I find the right ones.
Thanks,
Snyde

The harness has plenty of slack under the tank to free up its the clutch cable I would be worried about. I have three inch kick back riser on my dyna wide glide .clutch cable had to be replaced .

Thanks for the reply.
I ordered a set of 3.5" risers, they look like they'll give me enough rise and my clutch cable and wires will be long enough.
Snyde

I ended up buying 3.5" pullback risers. They're great!! It's like a new bike to me, much more enjoyable to ride!! I had plenty of stock harness and cable lengths for them. One of the best $45. I spent on the thing! Next thing is a good LED headlight for it, the stock light is crap, especially the low beam!