Hi Phil,
I got the idea from this post:
Thor ACE grill screen - iRV2 Forums
The OP used a metal version of the gutter guard, the item l used was only $4 and light/cut with scissors. The problem I found was finding mesh that had the right size holes for stopping stones and not air flow. The A.C.E. has a plastic inner molding, just use short enough self-tappers not to pierce the chrome outer and I found some rubber washers to go underneath.