I had a similar problem but no welder or torch - originally laid out the waterer area with posts on 8 ft centers for boards. I didn't like that at all - treated wood 2x6 was obviously not strong enough. Took those off and put up guard rail. The Milwaukee impact got a workout. Ship's auger and plug in Milwaukee low speed high torque drill made the corral easier than the waterer.  

Just built a corral this fall and set telephone pole posts on 6'-3" centers and used guard rail in the high stress areas - MUCH easier, very little cutting and drilling. 

Didn't have enough guard rail to finish so on the rest of the corral I used some local rough sawn oak full 2x10 that a fellow had left over from some building project 2 yr old and dry.

Pofarmer has a note in his signature line that says "experience is what you get just after you need it" - definitely true on these fencing projects! I'd like to see your cattle operation some time.

Jim at Dawn