At Nationals I actually spoke to several different coaches from all over the US and many many of them had attended mostly spilt format tournaments. There was not one negitive comment about the format. Sure you are going to have some who have to stay all day because they have wrestlers in different age brackets but what about the many, many that do not? The ones that still have to be there all day would be whether it was split format or not.
I would be happy to help in any way I can.