That wasn't in a row. Nor does Sasuke ever give any indication that he's cooling down unless he's forced into a position where his eye is unusable and explicitly states "My eye isn't working". Stop trying to disprove that Ameno has a cooldown, you sound dumb as all hell.
As many times as he has to before his time limit runs out. Kurama's full chakra is far far far beyond what a Flash Bijuu Dama is needed.
-Kurama Mode Naruto fights against Mokuryu. Gets a lot of chakra absorbed in the process.
You must be registered for see links
You must be registered for see links
-Gives Kakashi chakra.
You must be registered for see links
-Contributes the vast majority of the energy of this BD.
You must be registered for see links
-Used a shadow clone.
You must be registered for see links
-Used 5 small BD
You must be registered for see links
-Got blasted by the Juubi.
You must be registered for see links
All before he ran out of chakra. The BD he contributed far more than half of the energy to is far larger than his
You must be registered for see links
With a far larger blast.
You must be registered for see links
Minato also has more energy in him since he has Nature Energy, physical energy, and mental energy. That means more chakra since his chakra is made of 3 energies and not just 2. Instead of being 50 (using numbers as an example, please don't fall behind) physical energy and 50 mental energy, he takes in an equal amount of Nature Energy, thus it is 150 in total.
The BM Naruto feat of charging that Combo BD is already enough for Naruto to use over 2 Flash Bijuu Dama w/o having to exclude any of his other feats, like splitting his chakra among clones, giving some to Kakashi, and using 5 Bijuu Dama. Then there's the chakra Mokuryu absorbed. Minato easily uses 4-5 Flash BD at least before he runs out of chakra, and Sasuke can't dodge repeatedly.
Even if I agreed that he could spam Ameno in succession, instead of just letting the BD fly away, Minato can use S/T Barrier to suck it in and then redirect it so that it explodes right where Sasuke is. Not to mention he needs to be close by if he wants to fight Minato since Sasuke has no good ranged attacks and Minato can't fly, so Minato would only have to aim the BD so that it explodes and Sasuke can't dodge, even w/ Ameno due to him not being able to escape the range of the BD's explosion, which is due to Ameno's distance constraints.