Oh my God!You need to use your brain a little better. That was HIS genjutsu meaning the one that he actually casted on Obito. Not a genjutsu from his actual orginal eyes. Madara STATES HERE THAT HE IS ABLE TO USE THE GEDO MAZOU TO AMPLIFY HIS GENJUTSU TO WHERE HE IS ABLE TO CREATE ANYTHING HE WANTS. THIS REFERS BACK TO THE 10 TAILS AMPLIFYING MADARA'S TSUKUYOMI ONTO THE MOON WHEN HE BECOMES THE HOST. Honestly dude its not complex thinking at all. He is just using the power of the Gedou Mazou to strengthen his genjutsu on Obito in that page. When he becomes the host for the 10 tails he plans to use that massive power to strengthen his Tsukuyomi to be projected from the moon and those create his dream world. Madara's states earlier that he plans to reflect his eye techniques onto the moon by using the 10 tails powers.
This goes back to why Obito wants Sasuke because its starting to make sense. When Gaara asked Obito why he wanted Sasuke so bad, Obito told Gaara that he had "special eyes" and he couldn't let those eyes go to waste. He said he was trying to strengthen Sasuke's eyes and then later on we find out that Obito plans to sync Sasuke to the Gedo Mazou. Which he will need the Rinnegan to do so. This means he was planning for Sasuke to be the host of the 10tails. This explains why Obito wanted Sasuke to gain the EMS so badly.
For the mere fact that you assumed Madara can use Tsukuyomi through any spare Sharingan makes you one of the biggest idiots I have encountered on this forum. Now go away.