I don't know about the dry spot to stand in. Keep in mind that in Ontario we don't get the dry heat that you must get there, but what we find here is that in the summer when it is hot and dry, people here seem to have more trouble with cracking and chipping. That tells me that you should keep a wet spot somewhere that he has to stand in at least once a day -- a lot of people put it in front of the water trough.
I agree with going more rounded. This will help with the side chipping and also helps to reduce the amount of "spread pressure" on the toe. It does look like you could do more on the toe, and maybe, as suggested, increasing the roll will be enough.