I have them on both interstates, and both with Rattlebars heel toe shifters (and both with 13" shocks). My feet get sore riding on pegs only (and I had a bad habit of pointing my toes down off the front of pegs, and hitting things with those toes).
No lowering brackets for anything, because I like to lean.
The boards hit just a tad sooner than pegs, and my boards are ground off on the bottom/outside edges at 45*). With full length 13" shocks, you can really lean all you want, but they will drag a bit at max lean, and that's OK, they are on hinges and flex upward when you do hit (just like pegs).
After 10+ years both sets of my boards are a bit worse for wear chrome-wise, but this is to be expected putting gritty boots on them all the time. I don't care.
The Valk driver Cobra boards are really smaller/shorter Cobra passenger boards, because of the valve covers; there is just not enough room for full length boards. I only have 8.5E boots/feet, and with the heel toe, I do not get my whole boot on the left shifter-side board; there is physically just enough room for my boot, but it is too tight a fit between the pegs, so I ride with my toe angled out off the board. On hard left leans, I have to move that toe inboard, or the road can drag it off the board, and twist my knee painfully. I may have diddled with the shifter on the splines (one tooth up or down) because of the heel toe shifter (it's been a long time and can't remember).
Some guys who run Cobras without the heel toe shifter have found limited space to easily get the toe off the forward edge of the board, and under the shifter to upshift the really small valk shift peg (pushing down is never a problem). So they have also moved the shifter rod on the splines a tooth or so, and some have modified the shift arm to the longer/wider arm Honda Blackbird shifter, or cut the shift peg off, and drilled and tapped the arm for a longer Kuryakyn (Hog) Longhorn shift peg). I think the Cobras work better with heel toe shifters than without.
These are the Cobra
Swept foorbords, and I think the old rare Kuryakyn heel toe shifter, with the shift peg cut off and a Kury longhorn added. (I like the traditional Cobras better, but am not sure there is any real difference as far as function, though the swept look wider)
Traditional Cobras
One other thing. Some guys have split the difference between pegs and floorboards, and gone with Kuryakyn Iso Wings (which come without ends and you have to buy the valk driver adapters to mount right to the bike). Can be used with or without a heel toe shifter. You get better foot support than pegs, but less clearance issues than boards, and less than half the cost of Cobra boards.
Couldn't find a pic with Valk, but here is Wing.
