With most AIs, depending on exact dimensions, you will find somewhere in between 90-97 or more of gr H1000 with the 300 gr SMK. Mine ended in the middle and at 2960 with one hole. What more can you ask for?
Just a lot of different reamers, shoulder angles and dimensions out there.
That is the drawback of wildcats and why most will normally need custom dies.
I went the same (maybe a little more) on US869 also but did not go high enough to really make it work I think. Or the gun just did not like it.
Anyway, due to the reamer variances you really need to start low and work up.
My gun has the HS mag, which are shorter than some, so I started just under max COAL for the mag and it stayed there.