Re: 264 twist rate and bullet choices
You're probably fine in 9tw Fisherman.
Berger recommends an optimum twist under ICAO conditions(same conditions of BC rating). Seal level, 59deg, 0%Rh.
8tw puts the 140VLD Sg at or above 1.5 here, and this provides margin for all things affecting stability.
9tw puts Sg about ~1.3 at ICAO and there is no evidence yet that this would degrade accuracy for you. It might if your muzzle pressures are in excess(short barrel), or your crown is less than perfect.
What conditions will you be shooting in(elevation, temps)?
I've used 140VLDs in 8.5tw here at sea level, and around 50degs with fine performance.
My Sg is typically running ~1.4
I personally would not worry about 9tw unless I was challenging stability in another regard.