pretty much what Michael said: I think suit or no it can be quite difficult to completely avoid stings. You have to be very proactive in putting on the suit and making sure there are no gaps anywhwere- as when bees get angry they tend to find even the smallest hole. Also bees can sting right through many bee suits, leather gloves, denim jeans, etc. If you wear thick clothing that can stop the stingers being able to reach through. Also there is the matter of taking off the suit: I have a somewhat angry hive at the moment and I have found bees follow me from that hive up to 30 feet away and try to sting me when I go to take off my suit. So you’d definitely want to have the best suit you can get and be extra-vigilant- and make sure there is always another person nearby too.
I don’t think flow hives offer much additional protection to be honest- as you need to look into the super to see if it is capped, you need to remove it to inspect the brood and at the end of a season, etc.