I used to do snake talks at a zoo. Not with snakes that size though, and I certainly wouldn't see myself as an expert.
We always gave a warning about washing your hands - generally done as a joke so you didn't come across as being too dogmatic but we always pointed out that snakes have a better sense of smell than sight so you'd be better off not smelling like your pet hamster. Yes, they absolutely should have done this.
We never put ours on the floor because they are bloody fast when they want to be. You are not going to outrun it if it's decided to go, and they can get into some surprisingly small spaces. Having said that, we didn't have an outside area with a barrier so if we took them out we had to be able to hold on to them. I can't really picture the barrier so can't say whether the snake would be easily able to get over it quickly. Ours were noticeably more alert when outside though - loads of novel smells and movement to attract their attention, I found it far more stressful to manage a handling session outside then in our indoor venue.
We didn't handle them too soon after feeding as our reptile staff had advised us it could make them uncomfortable and grouchy so if it was very recently fed then there's a chance that it might result in a grumpy rather than a calm snake. And I have worries about the welfare - if it's cold then that's not great for the animal trying to digest a meal, and if it's warm, it's more alert and active.
My biggest concern though is that I did handle, regularly, two six foot pythons. They were bloody heavy and after twenty minutes of holding them my back and legs ached. The big snakes in the reptile house could only picked up by several people working together - two people just wouldn't cut it. When their enclosure was being cleaned out (before the zoo opened) EU were let out to roam around the public exhibit area and when it came to putting them back, they were too heavy to be lifted completely off the floor, they had to be sort of partly hauled back in, and left to move back in on their own. Two staff members with a snake that big? How did they move it out there and if something were to happen? How do they hope to control it? Snakes are seriously strong and I doubt two staff would stand a chance. I speak from experience of having one arm pinned to my side by a six foot long snake and being completely unable to move it, even with my other arm free...
I'd be uncomfortable with this, unless the barrier was higher or more solid than I am picturing. And I love snakes and worked with them for 12 years, including managing their interactions with the public.