I'm cooking a practice packer every weekend and I'm having better results checking and pulling when the flat is 186�+/-.
These are 15 lb choice IBP packers and must be pretty good,since they are finishing right at 1 hr/lb.
I cook a few hrs at 180�-190� and gradually raise it to 225�.
I still poke test it,and insta read several spots.
I let it set about 2hrs + in plastic ,with 1/2 cup beef stock.
Let cool on the counter for another 1/2 hr.
Not perfect,just the way we're approaching it.
If you're not worried about injection tracks,you can inject with Joe Ames' Fab B-lite.
Hope this helps a little.