You don't need indoor UV if your torotise is getting sunshine several times a week.I tried making few adjustments and some fidgeting but the UVB bulb never worked. So I finally decided that I would set up an outdoor screen enclosure for him. The mesh will be just big enough to prevent rodents and cats from getting through. Along with that plan comes more questions.
1. How long can I let my tortoise outside? Aiming for 3 to 5 times a week.
2. Is it ok that the humidity outside just ranges from 50 to 60?
3. I should aim for the same temp of 80 to 90F, right?
4. Does he have to be under direct sunlight?
5. Is it ok to soak him while being under the sun?
Your questions:
1. My general rule is one hour of access to sunshine per inch of tortoise. You can do this daily if you want, or twice a week is fine too.
2. That won't hurt anything as long as you soak after sunning, and keep the indoor housing humid. Humidity is often single digit here. Less than 16% most of the time.
3. Outside temps of high 70s to low 90s are good. They won't bask much when temps are higher, but that is okay.
4. No. There should always be shade available and places to hide. Don't worry about how much time the tortoise chooses to actually be in direct sun.
5. Yes, BUT do it very carefully. Monitor the water temp closely, and do it in such a way that as the sun moves, more and more shade overtakes the soaking tub. You should have to keep moving the tub more into the sun every few minutes. This way, if something happens to take your attention away from the tortoise, it won't end up in full sun and cook. It will instead end up in full shade and be fine.