Weaning of breast to sippy cup

[Finndod]

Hi there, currently going through a bit of a nightmare with 9 month old who is on a nursing strike and refusing to feed unless can catch him unawares when just waking up. Always been fed to sleep so proving very tricky. Refuses dummy and won't really entertain bottle either. He is on 3 meals a day but obviously he still requires milk until he is 1. Did not want BF journey to end like this but maybe now is the time to stop while he choose to rather than a battle at a later date. Been trying to express & put formula in his tommy Tippee sippy cup and he will take little bits but won't have one big feed as such. Has anyone else experience of this? Do you just leave the cup and let him have sips as and when? Are there better cups out there as with this because small amounts of milk in it he has to really tip the cup up high and often tips upside down and pours milk on ground. How many oz should he be having in a day now he is 9 months? Any advice greatly received. Thanks