Replacing Hoyt Super rest with Shibuya Ultima ... any advice?

For ages now I have had a Shibuya rest sitting in my archery bag waiting for me to fit it to my Hoyt Horizon riser ... but every time that I think about doing it, I look at the fairly hefty (maybe 4mm) pad that my plastic super rest is mounted on and as there is no equivalent mounting pad with the magnetic rest I get stuck wondering if I need to replicate the same distance from the riser (as the plunger is set to work with the existing rest) ... or do I just fit the new rest and redo my plunger positioning to keep the same amount of exposed plunger (arrow-side)... TBH I am not sure about any of this, particularly the effect and adjustment that I will need to make to my centreshot setup. Can anyone offer any help? Any advice would be gratefully received!!