Completely unresponsive.
No need for recess grooves or anything. Mod spacers have pad recess… so that eliminates that worry 
This setup allows you to keep your FHZ stock!!! Just switch out the axle, and add the mod spacers and BLAMO you got yourself a B.A. FHZ
I got the Mod Spacers from YYE guys!!! $4.50 a pack! I bought 12 packs!! hahaha. Y’all better hurry up and get some before I make my second swiping.
Also, Pro Z’s come with black/white MOD spacers (not the offstring ones).
Also, I added Silicone to the 4 holes of a Offstring Spacer. It has been curing all afternoon, tomorrow we will see if it works as a response 
Imagine my setup above with Black Mod Spacers instead of clear ones :o Someone sell me Black Mod Spacers from their Pro Z!!