Andy I only have experience in TX, but I will say there are a number of folks interested in small hay operations on this forum. Here are my thoughts. For 5-10 acres you will likely never see a return on your investment (ok maybe in 40 years). So if you are doing this for profit, my advice is dont. However, if you have money to burn then go for it. I suppose haying can be a hobby if you wish. It is certainly rewarding to have many excited and thankful customers if you produce a quality hay product. In East Texas there are many that bale weeds and still sell them. Don’t be that person!
For tractor size, it really depends on what type of bales. If small squares only, you can get buy with a smaller machine. If you want to go large round then you need big machines. For your property size I would go square, but perhaps talk to others in the area to see what they suggest. Once you decide this we can talk specifics about machines.