I appreciate that the following isn't the Apex Track Attack system but a fellow Hybridz member built, installed and ran a pushrod/rocker/inboard damper rear suspension on his car some time ago, I don't know if he is still active on here but a search of his past posts might give you some insight into how he fared with his system
https://forums.hybridz.org/topic/91914-rocker-arm-rear-suspension/