How much BM for a bottle refuser...?

lisac1017

DS is still being stubborn over the bottle, he likes the sippy better but it makes him spit up too much.  Our other options are the syringe and spoon feeding.  I go back to work this week for just Thurs and Fri. and planned to leave 15 oz of BM split into 1.5 oz servings to avoid wasting it. I am praying that if I'm gone all day, DS will magically drink up.  Since I always nurse, I have no clue how many ounces he should consume in the 10.5 hours I'll be gone. But I'm sure he won't drink close to what he should.  Is 15 oz a good amount to start with? I have some frozen too just in case.