The big trees can hold a ton of good staves if your willing to put in some work. You can get belly splits that don't need debarking and sapwood removal. I think what you need to do is find the straightest trees with the fewest limbs and no twist to the bark. Cut those trees. They will be the best. I have found that osage trees that grow in the bottom of a wooded valley near a creek or water source will be tall, straight, and have thick rings. I would suggest you cut what your equipment will handle. If you have a tractor that can haul out big logs then do it. But if you have to haul them out by hand or by quad, stick with smaller trees. Seal the ends as soon as you cut the tree. I prefer to split my trees into staves and debark/remove sapwood as soon as I can. I had a bunch of staves ruined after the bark loosened and they checked everywhere. Now I peal them and seal them, then seal them again. I have cut a bunch of osage over the last few years and these are just some of my opinions/methods. Find out what works best for you and good luck.