Ok, I'm way out of date here, but I qualified in 1990, and was teaching Year 2 in my first 5 years of my career with one (yes, one!) T.A. shared between the whole school.
I divided my class up into 3 groups - the 'good' readers, who I would make sure to hear twice a week (on Tuesdays and Thursdays) who were also choosing an 'own choice' book alongside 3 books from their tier of the reading scheme. Then came the 'middle tier' who I heard three times a week (Monday, Wednesday and Friday) who needed a bit more guidance, but were otherwise ok and progressing well. Then there were the ones who needed more support - I tried to hear them every single day (yes, really!) and helped them a lot more in their choice of book within their band of the reading scheme.
I had no break times, and no lunch times to fit all this in - I did try to hear readers during lesson times, but it was hard to do so in the mornings when it was more intensive maths, English, topic etc. But I did it. And now, many of my old students are teachers themselves (and still in touch with me - I don't know if I inspired them or cursed them!
) but the idea of having a T.A. in every class, or even one per Key Stage was but a distant dream back in the early nineties!
(I have to say that now I'm a private tutor teaching my specialist subject at GCSE level at home - the life a teacher these days is really stressful compared to the career I trained for
)