Ellen Sue Blakely,
I agree with your thoughts as well as Barbara Appelbaum’s. The weight is an issue. If you go with grommets, keep in mind that these too would be invasive and would need to be evenly distributed to minimize stress and distortion. I also would advise that the grommets be backed with a thick awning fabric behind the painting to reduce some of the stress on the canvas. There may be ways of using velco strips if appropriate adhesives are tested. There are also possibilities of creating “support” from behind to reduce hanging stress. If you do have to repeatedly store the painting I would recommend rolling it on a sono tube of significant diameter.
I would be happy to talk to you more about this project and might be able to visit on a weekend in June as I live in Cheyenne and work between there and Fort Collins. Feel free to email me, firstname.lastname@example.org