Okay, I have a smalllllll horse farm, almost 9 acres, and I need to put up new fencing. I was looking at getting 4 inch by 8 ft posts (we're on the morraine so they ain't coming out!), and looking to space them 10 feet apart, is this okay? or should I do the 5 inch posts, and 10 feet apart, or just stick with the 4 inch posts and 8 feet apart. I'm planning on putting 3 boards up, and two lines of electric poly rope off the boards (at shoulder height, and at knee height) to keep the horses from touching the fencing, which is something I KNOW works well. HELPPPP PLEASE, THIS IS URGENT, i need to place my post order SOOON, i move in like 3 weeks!