Just a sugestion from someone else's experience;
On one of my many junkyard trips I saw a Cherokee with short (front to back) bump stop extenders like yours.
The "frame" was stress cracked at both ends of the square tubing.
From looking at that Jeep, I think he liked to jump it, plus it didn't have much lift.
So, if I were making the extensions I would have a much longer mounting surface with a slight curve at the ends to to distribute the stress.
Mike