Hi great idea and it works great, it's not as simple as it looks , but the end more than makes up for the irritation .
first off if you just shift to the first set of holes you only gain about an inch so i opted to shift to the last set of holes .
the ones that remain after you remove the web. to do that on my 77 hatchback i had to cut the first set away with a 4 inch grinder , then moved the bumper mount back and re installed the spring shackle mount. reatached the rear shocks and found that the upper bumper bolts were unreachable. so back to the old drawing board this time i bolted the upper bolts to the mounts and reinstalled .
now it looks great with about 1 inch clearance all around and i don't need the rubber filler panel at all.
sorry for the long post and thanks for the idea loved it . moonman.