Went down to the home improvement center purchased a roll of black fiberglass window screen material that was wider than the opening to the heat exchangers and cut to about 12” longer for the height.
Mesure twice, can always trim some later.
Installed by getting it in through one of the larger bottom openings. Used the black rubber / plastic piece at the top that keeps the ram air going into the opening and not spilling over the top into the engine bay by tucking
it in between it and the body cross member. I let the total wide to cover the opening to the air filter. On the bottom worked it to tuck
into the lower air dam and the bumper seem to hold.
Some of the tucks I did have to rework till it was happily secured.
I live in the Phoenix Arizona area and in fact was on vacation back early July and crossed Death Valley CA on the day it hit 123, ran the air and stopped to take some pictures and zero problems with any over heating.
Wish I had or could take and post some pictures for you.
I spent 3 years in Michigan and know what a bug clogged fins can do to a heating problem. Given the stack of heat exchangers other than removing the front one to clean would be all but imposable. Just shaking or worst case remove the screen and clean or replace should not be all that hard. Took a couple of trips to northern Arizona just shaking it knocked off the bugs collected.