It's certain that he already had EMS during their final battle and if we consider the reactions of MS Sasuke and EMS Sasuke to their respective Susanoo's, I bet that even if Madara in MS state might have refrained from using Susanoo due to it's strain, EMS Madara would have most probably spammed it.
Besides, we've seen what Mokuton can do, I don't think that Madara could have kept up to it without the use of a PS. :shrug: