I hope SonicMS didn't actually measure the height adjustment with their fingers. MPP in their coilover installation video shows very precisely in millimiters how to adjust to recommended height using thread measurements and they state this should be done before installing the coilover. So basically before you can even tell how many finger gap you have. See 1:42 marker:
I presume you asked them to watch this video and follow it precisely. There's a lot of important tips in there that if you don't follow you could actually do long term damage to your bushings and suspension.
If I were you, I would check their work and measure the height the proper way and see if they did it to spec. You can go out of spec but then you will not get the optimum performance the coilovers where specifically designed and tuned for. MMP took great care to tune these coilovers using software and road testing on PageMill mountain road in California.