Looking down from the top, I would make it more of a coke bottle shape, with the thickest part of the palm swell about 1/3 of the distance between the pin and the thong hole back from the pin. Looking from the butt end forward, make the profile a modified oval, with the the dia. of the top of the oval about 1.5 times the dia. of the of the bottom of the oval. Since you have a good looking knife there, it might be worth making a handle of scrap wood and checking my suggestion for comfort. My suggestions fit my hand. BTW, nice knife.
Tim