One thing about grains-- they have a tendency to revert to normal prices during a year's time. This is because the crops are renewed each year and producers can switch acreage etc. This is totally unlike other physical commodities like oil that need a lot of infrastructure to make a difference in the market. This is in part why oil will continue moving upwards with many dips along the way. By the way, there are other agricultural commodities that take a while to get back to normal. These would include OJ and Coffee where it takes quite a while to develop new groves and trees etc to increase the supply. Grains are not that way. I like the grains play due to the yearly seasonality of prices. I will be shortly entering the Long 4th of July Beans, Short Thanksgiving Beans spread and I'll hold that (and add to it), into May, when I will look to reverse this and go the other way.
With regards to the TA question, I use exactly the same tools for these markets as well