I would say if you are able to control the kyubi, use pf susanoo and fight then you will need kyubi equivalent chakra.I cannot. But most topics like this are resolved based on evidence provided by the manga at the moment. Unless new sources of evidence appear to suggest otherwise it is only logical to take what we have and use it to make judgements. The manga suggests that madara has large chakra reserves given his feats. But there is not enough evidence to say whether it can match hashirama's or not. however hashirama's has been compared to the kyuubi which was previousely know to be the being without equal interms of chakra bar the juubi. Given this we can draw conclusions on hashirama's chakra levels but not madara's.
SM modal hashi has kyubi equivalent chakra. Madara solos him for 24 hours while controlling the kyubi which is extremely taxing. And PF susanoo.