Just...trill...
The trick is for me is, trill as if there is no end to it. Don't anticipate or emphasise the 32nd notes! Only escape to the 32nd notes at the very last possible moment - and even when it is later than the very last possible moment, it will still be fine!
Practise just the trill hands together first, as if it's never ending. Then, practise with the escape (32nd notes) but without a sense of beat - just go to the escape when you're ready to come out of the trill. Make sure that there is no break between the trill and the escape - as though the escape is part of the trill. And then practise it in time by feeling the 3rd, 4th, and 1st beat (of the next bar) only - this will give you an idea of how late you can really play those 32nd notes (I bet it's much, much, MUCH later than you think they need to be).
Working out the trills precisely is only a good idea if the trill is short. When it is this long, it is rather silly. So...just...trill...
Measures 149-152 is the same really...just play the written 32nd notes as late as possible. Don't count in eight notes, but in quarter notes. Feel the beat this way and you will know when the right moment to escape is.
Hope that helps ^^ and have fun with this magnificent work!