I know nothing of hinge backs, but RFs are a relatively social species. We had a member here a couple of years ago that was advised to separate her two baby RFs and she listened to someone like you, instead of the multiple people that told her to separate them. Six weeks later she was back asking what to do as one had eaten the tail and most of the back leg of the other.Also in a decent sized area there should not be any rivalry problems with these until they reach puberty or possibly get too crowded. My Red foots and Hingebacks do fine living together. Sometimes I see these opinions taken too far on here and vehemently disagree.
How many Gopherus babies have you raised up there in Eugene? Are you sure they are just like the other species you've raised, or might their temperament be different than the ones you know? I don't think you have any idea what you are talking about. I don't think you have any Gopherus experience, and I think you are offering bad advice based on ignorance. I call attention to it not to start an argument, but so that people reading know to dismiss your baseless assertions. Little Gopherus can and will attack or intimidate each other when kept in pairs. I know this from repeated first hand experience with the species in question. Is this an opinion taken too far? Here's what can happen when people listen to your advice:
https://tortoiseforum.org/threads/bad-day-for-baby.114328/
Why don't you have a look at that thread and then come back and tell the OP that they won't have a problem until puberty. Have a look at the picture of a baby tortoise with a bloody hole where its eye used to be and then tell me all about your vehement disagreement. Or the lady with the RF that got its tail and leg chewed off over a period of weeks. Do you vehemently disagree with that too?