Second the opinion on 30" barrel and 1-11 twist. I built my HG (under 100lb weight limit), with a 10" BAT action with 30" 1.875" to 1.5" barrel with 1-10. It shoots very good, but the 300 wsm is really more suited for 1-11 with 190-210 bullets. My next barrel will be 1-10 and now everyone is going with 1-11. Start with 210 JLKs as a recommendation.
Use a PA rules tapered barrel and if 700 and 30" I would recommend sleeving the action.
Caution on the 30" barrel though, you will need to really talk to a good 1k smith before you buy components (stock, barrel, scope and action) and start building. Depending on components, you could have a difficult time making 16.5lb weight limit for BR competition under PA rules and limit is 17 lbs for IBS or NBRA. Most end up cutting back to 28" and with LG add good muzzle brake. If go with 30" you will definitely need to flute the barrel and that adds $150-180. Night Force scope will also make it hard to make weight, go with Leupold 1" or 30mm tubes or something similar.
Good Luck
BH