Bar risers

I'm trying to gain some acreage between the handlebars and footpegs on my WRR. I was wondering if anybody has put bar risers under a Highway Dirt Bars set up? What type/brand did you use? And how tall of a riser can you use on this bike before causing cable issues? And finally, I'm about to order lowered and shifted back foot pegs from Radon who manufactures these somewhere in a deep dark corner of Europe, who I found on this forum.

My back is wearing out...

Any comments will be appreciated...