[Mike Taylor 3601]

I have had stands shimmed that much before,no problem just make sure bolts are long enough, I would make sure they engage all the threads available.
Best spot will have roller slightly toward intake when closed, centered about mid way, slightly toward exhaust at max lift.
A lot of people don't like the tools Jesel,T&D supply for stand height,alot say throw them in garbage,but I disagree,I like them and have always came up really close to where I needed to be.

How much longer are your valves? I have had stuff with long valves before that I had to have different stands made for,when you get up so high the roller will set out towards exhaust on tip of valve,have had custom stands made that moved whole stand towards intake,while was at it had stand made thicker so would have less or no shims.
On new set Jesel exchanged for the difference in cost of regular stand and custom stand was'nt much at all,guess they still will do this has been awhile since had to do that
Mike Taylor 3601.