Advice for tortoise virgin

[Neilgerard]

Hi, I'm a total tortoise virgin so I'm learning a lot from this site. After extensive research I bought a leopard tortoise CB12, now named Spartacus. He has settled in well and is eating a variety of garden weeds and flowers, I also offer him Florette dusted with nutrabal. He drinks well and uses his water dish to urinate in. His tortoise table is heated with a uv heat lamp giving a basking temp of 90 degrees and a cool area temp of 70 degrees. The substrate I'm using is the one recommended by the seller and is pelleted compressed straw, is this the best substrate for my leopard or should I go down the topsoil/playsand route? My tortoise table is made from laminated chipboard and I don't want the moisture from any substrate to affect this. Thanks in advance.