I highly recommend the cereal killer. I’ve had one for about 3 years now and it’s been trouble free. Replaced the Barley Crusher with it. I recommend staying as far as you can from the Barley Crusher since the one I had didn’t even work for a year!
There’s a thread here that documents my issues.
BTW, you should have a fair amount of flour when you’re done crushing. For BIAB I’ve crushed as fine as .028 but have opened up the gap to bring my efficiency numbers into a more consistent range. I do sometimes have a thick paste in the bag from flour, no big deal. Flour will not cause astringency. pH would be your issue if you have astringent tasting beers.
