well where are the IWR shinobi getting their chakra from are they indenpendent limited sources like living ninja or are they only as powerful as the userGaras dad as jinchuriki I guess I support, but did you not read my post at all, he has legendary shinobi at his disposal, he can have tons of IWR shinobis seal with him which would cut that time down so much. probably faster then Akatsuki sealing because he could have so many people doing.
but yeah using the other jin to focus on the jutsu makes more sense, depending on madara's status at the time he'd need some others to stand guard since madara can come out of nowhere and sucker kabuto into a genjutsu and make him release IWR.