Ok so looking around for info on the silver eyes I mostly found stuff that has already been discussed here.
The only two new thighs I could bring up are
1:The silver eyes can't even trigger without Grimm being close.
Ruby straight up can't use them unless there's Grimms around, of course if DB rules SE magic counts they would obviously allow the trigger.
In fact this for me confirms that they will equalize Grimm to Magic/Black Blood to some extent because otherwise Ruby wouldn't get to use the silver eyes in the first place, and there's no way in hell DB would allow Ruby to lose without showcasing her most powerful stuff.
2:The silver eyes don't necessarily kill you.
If a Grimm is powerful enough they can break free from the petrification or just end up stunned for a bit (or blinded)
I think this is the angle DB will take, Maka being stronger will end up petrified but will break free and end the fight.
Also if somehow Soul ends up being the only one turned to stone he could still use his madness Soundwaves inside the stone if DB rules that he would resist the effects.