Some good points made. Weight has been top of the list for me. Worried too much on barrel muzzle OD dimensions, barrel length<---->velocity, etc. and not enough about weight. I've luckily avoided the twist rate issue so far by using "when in doubt, go faster" with an example being my 6.5-06AI that is 1:8" and throws 120's as well as 160's.
The other advice would be having an in-depth conversation with the gunsmith about ammo, especially if you handload. If you know the bullet you want, make up some dummy loads and make sure it's throated for exactly what you want. SAAMI chamberings can seem too generous, and there's a chance you'll have buyer's remorse if you have your heart set on a specific bullet and don't make that clear upfront.
