you said white oak right, if you go 64" ntn with a pyramid design, 4" grip, 1 1/2" long fades, go 2" wide at the fades and straight taper to 1/2" tips I feel is your best shot, white oak is pretty tough to break, you will probably get some set and that may help your cause, don't worry about all the forward grip stuff on this one I have built with these dimensions and went to 30".
with a bulbous grip your gonna lose a little bit of that ape arm thing ya got going anyway