Yes, just cut them off at the subpanel. Make a new bracket with some angle and move them inward.
Make the brackets first before you cut the ribs off.
Check the angle of the brackets from the back of the subpanel.
The subpanel has a bend across it, so you will need to put a bend in your bracket. You can see how I put a relief cut in the angle where the bend is.
Then you can drill the holes in the bracket and match them to the ribs.
Draw a line on the ribs and then cut them off.
Once you have your panel layout figured out, reposition the cut off aft rib pieces inward. You can draw a line between the prepunched holes on the panel and this will help you locate the new position of the holes on the panel where it gets screwed onto the end of the ribs. Use some clecos to hold them in place and then drill the bracket to the subpanel.