What do you mean by base? If you are talking about substrate then a lot of people on here like aquasoil. I use fluorite myself.
Based upon what I've read, under gravel heating is not required. Also from what I've read, it's better to add a lot of fast growing plants to start off in order to keep algae in check, then swap out those plants for what you want once the tank is more established. I'm sure more knowledgeable people will chime in so hang tight