A couple of things I noticed:
1. I don't know how it is where you are, but my tortoises would fry in there with no shade in the summer. Do you live in a cooler area?
2. Paint trays are too slick, too deep and the sides are too steep. Some tortoises just aren't comfortable with them and so they don't drink. Some tortoises flip in them and either cook in the sun or drown. Terra cotta plant saucers are cheap and work much better in my experience.
I find the paint trays are great water holes for torts to get in and out as long as they can not enter on any side except the side with the ramp and drill holes in the plastic so it never gets past a certain water level if it rains. I run a knife over the surface numerous times so that the tort has plenty of friction. All this put together means he can soak in whatever water level he chooses. Best part is you can buy the big trays for like $3. Just my two cents!
That's great to get your tortoise out for some sun!
It is still a good idea to put a piece of wood across the sort end. That will add shade and a spot to hide in. Maybe a paver or two here and there, a log, potted plant submerged into the soil, etc.....