I love those hides! Very pleasing to look at.

I see you've got some stick-on dials to measure temps, are those your only thermometers? Unfortunately, those ones are notoriously inaccurate up to +-10 degrees, and the sticky adhesive on the back is known to come off and get stuck to snakes, which is less than ideal. I'd suggest getting digital thermometers, if you don't have them already.

You mention moving things around for the UTH, which if this is his first feeding day with you, I'd recommend against. You want him to settle in without any handling for at least two days after the first feeding. That's the minimum -- a lot of folks will suggest only handling after 3 consecutive successful feedings to ensure that all is well before handling them. He'll figure it out if your setup's as it should be, and regulated with a thermostat to prevent possible burns.

As for ingesting substrate, that only becomes a problem if your husbandry is off. They've survived in the wild for thousands of years without our help, getting dirt and who-knows-what all over their prey before they eat it, so a few pieces of substrate aren't going to hurt him.

This is just a suggestion, but I'm seeing a lot of open space in the tank. I'd suggest putting in some leaf litter or fake plants from the dollar store to give your snake some added security. They're very keen on feeling things around them as they move, makes them feel safe and hidden.