Re: Barrel recommendations
A 1-8 may, it may not like the 80 g. It will shot them it just might stabalize them as well as another twist could. I normally choose the bullet I intend to shoot the most and get the twist for that. If other weight bullets work, great. If not at least I know what I want to shoot mostly will work well.
You are correct about the barrel blank. It will come contoured to your choice and rifled from one end to the other. The smith will turn, thread, chamber, crown, and fit the barrel to your specific action.