Your pictures are very, very tiny. I'm sure your camera takes larger pics; why do you resize them this much? Photobucket accepts larger pics without a problem. Try uploading some bigger pictures, also of the unknown tree for ID.
The tiller looks pretty good for now. Are you working on a short string? This would be the time to go to the short string, and not use a long string any more. If this is the short string, I would advice you to take some wood off the handle and the outer limbs. Basically, the inner one third is a bit stiff, and the outer one third is a bit stiff as well. The center one third of each limb is just fine.
Hard maple is not exactly a very dense wood for nock overlays. But they should work, if you glue them on in the right way and if you file in the grooves correctly. I'd need to see a picture to confirm that, but judging by the fact that the nock starts splitting, I'm assuming the overlays has not been grooved correctly. Look up some examples of nice nock overlays on this forum, and copy that to your bow nocks.