Ok thank you I have many Mediterranean tortoise, but now is my first time with sulcata (baby) I am so excited! I am waiting forGreetings, while our young Sully was in an enclosure, we used a mix of coco coir, peatmoss and eventually just plain old cypress mulch. Many like to get and use fine or medium grade orchid bark, but i never used. The substrates you have listed will be fine, wet them down well and then place in your enclosure. You can mix, doesnt have to be one or the other..
Good luck!