I doubt he could create many massive Bijuu-Rikudo FRS variants with the chakra he has in that form, especially when each shadow clone would have 1/x of the original's chakra. And anyways, if YRS couldn't even cut JJ Madara, and JJ Madara is far less durable than PS, then even the combined jutsu would probably fail. I mean, Sasuke's Chidori Eiso could bisect SHINJU Madara with ease (whereas YRS failed against a weaker Madara), and even Shinju Madara is less durable than PS. Genuinely don't see how the RS combo would beat Madara's PS in this form, since this form's RS combo would logically be much weaker than the RSM one.