How much rearward restriction is there ? - just wondering if you could take a bit off the back of the inner rails ?
EDIT - this guy has done a full write up and shows cutting the inner rails to regain full travel.
That’s a super helpful find! It also proves I wasn’t imagining it. Thanks CRBDEANO 
The Jass fitting guide does say to trim the rails a bit. I also mentioned I had to trim the rails when I wrote the guide in this thread (which should be read as a supplementary guide to the Jass performance instructions)
Yeah I did trim the inner rails as much as I safely could but the rearward travel is still restricted which is really disappointing when they claim it doesn’t…