Your doing WAYYYYYYY better than I
When I first discovered this situation on my rig I had 3/4" from end of lever to the throttle stop screw.
Take 2x4 or.. heck you cars window squeegee and find away to prop it in the the car holding the pedal to the medal, and then look at you last link and the throttle stop screw. Still 1/8" ?
I would GUESS that you have some wear and tear of the little ball joints etc. therefor that tiny play creates motion inside each link prior to moving the next link and so on till it actualy moves the IP's throttle linkage. That tiny play at each link adds up.
I had to shorten some of my links to take up this play. (ALOT) but remember mine was excessive and bastardized. I started at the furthest away link (pedal's) and worked forward till my actual foot pedal's range of movement on the levers prior to the IP was maximized. I then adjusted levers right at the last link before the IP to make sure that my new foot pedal's range of motion was used effectively to move the IP's linkage thru its proper range of motion.
My linkage is made of a mix match of MB but it is void of all the ancillary linkages that the car has, yet I think conceptually the concept would still apply though. Those more in the know will either Kill me (understandably) for the missinformation I just accidently spread or add to it with far better detail.
thatttt being said...... Is 1/8th of an inch worth worrying about???? btw... Thats what Ive ended up with too.