Hiking and pace are very mental. It’s someone is slower than the rest of the group they should set the pace. You need to make sure they don’t fall behind because that will make them go even slower because they will lose the friendly chit chat and get discouraged.
You want the most experience hikers on the front and back. They both are needed to keep you group together but back is the just important unless you need a good navigator. Treat it like they did the LoTR put your Gandolf and Aragorn in the front and back while you hike
I always say “moderation in everything, including moderation” often as well