"Reinforce the hypotenuse"
Care to elaborate?
I was just thinking out loud, feel free to ignore me.
There is an angle due to the 2.5mm offset. If they are adjustable in and out then you can keep online with the slope, rather than increasing the angle by moving it down the chainstay.
* <- pedal
**
***
**** <-tensioner offset slightly
***** <- cog
* <- pedal
**
***
***** <-tensioner not offset
***** <- cog
Does that make sense? I haven't really had a chance to inspect these things.