We hang deer feeders by a home-made tripod constructed from three 12 foot or 14 foot 2X4s (or 4X4,s , depending on how big the feeder ) and t-hinges. Put a large eye bolt where the hinges come togather and hang the feeder from it.
We have found that bolting a boat winch to one leg of the tripod is necessary to hoist the feeder because of the weight of a full feeder.
The advantage if this set-up is the ease of relocating the feeder and removing it in the off season.
I recently made an 8 ft. tripod for my 30 gal. feeder. Welded some angled pipe onto a 1/8" plate and bolted the plate(bracket) to the barrel using rubber washers and silicone to prevent leaks. Then I used a larger dia. pipe(legs) to slide over the brackets and bolted together. The legs can be easily removed for transport. Works really well. I have to back my truck up to it to fill is the only bad thing.
As a Taxidermist I look at hundreds of Whitetail Bucks every year. I know that I have seen many different ways people judge the size of racks on live deer. I think for the most part they all are pretty close. I'm going to give you some measurements that I have noticed being right on in just about every deer. We have used it in the last couple years and have only been off by about 5-6 inches. We do study the deer while bowhunting so we get a little more time to look at them....