We appreciate the effort, but Bakuton is really something that should be handled by staff. But just for future reference, chakra costs for jutsu at each rank are set and may not deviate from the pre-established guidelines. Also, for advanced natures of any kind you would really have to expound more upon the history as the apps are scrutinized more than a normal clan app. And the clay thing isn't really bakuton. The mouths which formed the clay were a kinjutsu that was completely seperate from Deidara's Bakuton, he was simply capable of imbuing them with explosive chakra. Finally, the jutsu would have needed to have been nerfed before this would have been approved as well.
I'm sorry if this is the ability you wanted your character to have, but you will have to choose another clan for the time being. Staff will revisit Bakuton eventually, but I wouldn't advise waiting around for it as it is not a priority at the moment.