30 is fine for an ambient day and night. 34 is not as warm as I would like it under the basking lamp. 36-37 would be better. No need for 100% humidity. 80%, or something near there will get the job done.
I have done the experiment of constant very high humidity @Tom mentions. I have removed all overhead direct heat sources and only indirect heat was used to ensure the humidity is true everywhere in the closed chamber. After 8 months of constant humidity averaging 90% (85-90% during the day and 95-99% at night) I can report no health issues. However it did have some adverse effects on shell growth. While the baby leopard tortoise didn't pyramid, keratin forming the scutes came in noticeably thicker making the vertebrae scutes appear somewhat swollen and the growth rings failed to form properly. It just looks as continues growth instead of rings. As the spring came the yearling now spends full days outdoor at moderate 45-60% humidity outdoors and nights at very high humidity indoors. I am since beginning to see nice fine ring formation and thinner keratin layer.
This suggests that daily humidity variations or achieving a moderate sweet spot grows the shell more cosmetically perfect then constant very high humidity.
When you build your new enclosure, you might as well go big. 48x24" is good for a hatchling, but your tortoise will outgrow that pretty quickly. So you won't be using a 48x24" enclosure for "a long time". I build mine from plywood and line the bottom with thick plastic sheeting to hold the damp substrate.
It would be very difficult (but not impossible) for me to maintain 100% humidity here. That being the case, I have never raised one with humidity constantly that high, so I don't know what will happen. If you want to do an experiment and see, we will all learn from it. Or you could add ventilation and reduce your humidity to levels that have already been tried and tested.
I grew my Sudan babies with the conditions listed in the care sheet. 80%ish humidity, 80 degree ambient temp that rises to 90ish during the day, and a 100 degree basking spot. They also went outside for sunning sessions in my dry climate here about 5-6 days a week. Only an hour or so for babies and gradually more time outside as they gain size.
I have done the experiment of constant very high humidity @Tom mentions. I have removed all overhead direct heat sources and only indirect heat was used to ensure the humidity is true everywhere in the closed chamber. After 8 months of constant humidity averaging 90% (85-90% during the day and 95-99% at night) I can report no health issues. However it did have some adverse effects on shell growth. While the baby leopard tortoise didn't pyramid, keratin forming the scutes came in noticeably thicker making the vertebrae scutes appear somewhat swollen and the growth rings failed to form properly. It just looks as continues growth instead of rings. As the spring came the yearling now spends full days outdoor at moderate 45-60% humidity outdoors and nights at very high humidity indoors. I am since beginning to see nice fine ring formation and thinner keratin layer.
This suggests that daily humidity variations or achieving a moderate sweet spot grows the shell more cosmetically perfect then constant very high humidity.