Hey machine, like isf_21 asked, why? Is there a particular reason..
I would always encourage the traditional one handed thumb in the ball hook, although I bowl 2 hands due to a real hourglass thumb, that swells up and shrinks every few frames.. Frustrating, as well as taking tape in and out all the time.. It really got me down, then went one handed thumbless, to eventually 2 hands.. I love it, but it is hard work.. Many people think it is an easy ride!! It's not, u need to practise, there are no shortcuts here..U may (depending on your level of ability) see a relatively quick improvement, but it will plateau just as quick, then u better have a good spare game and read lanes well..
Anyway, love to know exactly why?