The 1 in 10 twist is the best all round twist for 200 gr to 300 grain bullets, But if you are
only going to shoot 300 grain bullets then the 1 in 9.2 ,9.25 or 9.5 would 'probably" be
better. (No proof of that just a hunch)>
If you are planning to build a monster 338 (Excalibur or bigger the fast twist is not nessary).
We use a 1:10 on a 338 Lapua using 300grn SMK's. No problems with stabilization so far. I know it is not a far shot, but I picked an empty shotgun shell off of a backstop this past weekend at 100yrds through the middle dead center with the described rifle and bullet above.
"Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it.  But small is the gate and narrow the road that leads to life, and only a few find it.
If you find your self in a fair fight, your tactics suck!- Marine 1st Sergeant Jim Ryfinger
Friends don't let friends develop canonitis!-chucknbach
arguing over the internet is like the special Olympics....even if you win, you are still...special!
This is only my opinion so take it with a grain of salt but I wonder how much of this 9.2, 9.3, 9.whatever stuff comes from some of these computer software programs that you input the information and it calculates "the perfect" twist rate.
I am always open for something better but when you have guys like Shawn Carlock, Kirby Allen and Dan Lilja all saying 1-10, well, that's good enough for me.