A variety of thickness's is always good, some of the smaller branch stuff could be cut at 1" thick and then that should be close to useable in a yr, 50 and 100 thick are also good on suitable sized sections, with your main trunk I would do thus... my preference is to take slabs off paralell to the outside of the trunk until down to within 50 to 60 of the center of the small end, then either flip it over and repeat, if flipping is not an option lift large end up until the bottom bark side is paralell with rails (if cutting with a lucas) and take slabs off, this will give you a wedge shape center slab but that can be fixed later, all this gives you grain that is paralell to the cut edge of slabs /boards. Pete.