My castor wheels are not adjustable.  I'm not sure if on later models that was offered.  It would have to be a hydraulic adjustment anyway, as this tilting requirement is ever changing.
One thing I notice is that the S tines have very little clearance even when up. So my tendency is to raise the front of the rake, making the whole unit not level, so when the rollers are angled, one side goes up  and the other down.  One could counteract this if you could tilt it.  
Problem, of course starts to be that you have too many controls to deal with.  I have a home made third link (that doesn't work very well, as it doesn't hold position) so that, along with the three Harley circuits and the 3PH control, make for a rather complex operation.  Actually, I bought another joystick lever from JD with the toggle switch in the top, and put this on my remote valve to control the Harley electro hydraulic valve.  Works quite slick!  But I tell you.  I put in some very long days last weekend and by the end, I could barely operate any of this stuff effectively anymore as my brain was totally fried!