I have high bars and I was considering going a bit lower, and bought the 8cm standard bars from Motobins ( the £29.75 ones) last week.
Main reason I was considering them was I thought I would need them to fit my fairing, anyway I tried to put the standard bars on, and realized pretty quickly there was no way they were going on with the brake line I had ( way too long), this was more to do with the width of the bars that was dropping from about 710 to 640mm.
So my advice would be when doing your calculations pay attention to the width of the bars also.
Next step I checked the Motobins and Motorworks sites for shorter handlebar brake lines, I may be going blind but could not see them, anyway, I gave up put back the high bars and fitted the fairing, it actually turned out fine and so I am probably going to stay with the high bars.
However decided to e-mail Motobins and ask them their advise on brake line and clutch cable, they replied very quickly ( after a day) with all the details and links to the parts that I could not find visa the website menus.
So my advise would be when getting your bars e-mail or call Motobins/ Motorworks/Sherlocks and ask them what you need, I found the Motobins guys very helpful.
Here is my bike with the high bars and a small fairing
