Seems odd that you were getting fletch contact with the riser. If center shot is set the same, then I would think you should get the same amount of clearance or contact at the riser no matter which rest you're using.

Maybe the rest was dropping too quickly? The idea is to have the arrow supported as long as possible to offer as much guidance as possible, and then drop out of the way just before the fletch passes by. If it drops too quickly then there's nothing supporting the arrow as the string is pushing it, so I could see where you might get some strange flight and unusual contact.

I'm currently shooting a TT on my Liberty & it works just fine. As similar as the Justice is I would think it should work as well. But both the TT and the GKF are great rests so you can't go wrong with either.