I'm 100% positive your intentions are excellent, but as an FO, there is no "I'll sit them" down unless you're referring to the top of descent announcement. The CA is the one who will sit them down. If it's really bumpy and you feel safety is an issue, this would be a time to do your best passive FO comment Iike "seatbelt sign is off, you think someone may be up an around."

I had a CA tell me recently that an FO was resetting the parking break at the gate I order to keep the clock going. This blew my mind that any FO would do that.

I totally get you're doing what's believed to be the best course of action, and there are many, but I can see some CAs maybe not liking that as much.