Will, suits have never been cheap. I was into them to some extent back in the 70's. Baker's version in the Laurentis King Kong inspired a friend and I for that halloween, until we checked prices. Then we tried to make them. Hey, masks & prosthetics & such were easy. But so much latex, so much hair, and more hair, and more hair...and artifical hair looks like so many drowned rasta rats without a bunch of care. Even the expensive ones looked fairly horrible in daylight. Planet of the Apes made extra effort to clothe as much area as possible because anything exposed was such a PITA (of course they had armies of them). Is cover a possibility? Otherwise, as others have said, go for evening or shade. Something to take the stage lights off the suit. And as Martian said, half the illusion is in the movement. Baker's suit worked fairly well because he studied apes extensively for that role.
With all that, I do hope you come up with something effective. Looking forward to reading about it.