I have an easy way to do this.
Add the options below to your looprelax flag file:
The looprelax will do a initial repack and minimization followed by JUST 2 times of KIC perturbation and a final full repack.
This will make a small change of your loop backbone conformation, and you can generate 20 decoys or more and select the one which have the lowest energy or the minimal loop backbone changes.
I think loop_backrub_mover can refine your loops and make a smaller scale conformation changes of backbone than KIC/CCD, but it was not included in looprelax in Rosetta3.1.