As you stated you've to be in HKG on that evening, taking the later flight would be way too big risk.

Take the earlier flight. You can go landside and stock on some Swiss chocolates and/or looking for a FTer at the airport that can guest you into the lounge

The later connection will still work in 95%+ or so of all times (LX usually holds their long hauls quite a bit for connecting pax), but considering we're talking late December, snow might happen, turn-around times on LX are industrial-low (ie, they can't usually make up much time during the day if there is some delay from de-icing or otherwise) - all taking it into account, I'd go with safety first.