Well Naruto's chakra is 1,000Xs larger in Rikudou mode so in theory he could make 100,000 clones to help him train with for any new jutsu. The problem with that is if Naruto uses 1,000 clones for normal training then the stress of 2,000 clones would be double and 4,000 clones would be double that exc... In theory Naruto could learn any difficult and complexed jutsu within hours but would be comatose for a few days after.
As for using clones for battle I think Naruto could use around 1,000 clones and they would have the same strength as Naruto in base mode along with the added bonus of the rikudou mode granting him a chakra boost he could use 2 clones to make the FRS so Naruto could throw 500 FRS. Over kill but it possible.
Also this is nothing compaired to Naruto super sayin 3Rikudou sage mode, his chakra increases double and his body is stronger even the clones would be extreemly durable. We figured this out after Naruto V Kyuubi. The kyuubi pounced on a clone and it was still alive, only after its job was done did it poof. Also not only is the biju chakra surrounding Naruto but so is the katas. I have a feeling that the katas and the rikudou cloak are going to encase Naruto in an em penetrating shield that would be as great as susano.