That weight gainer is crap, there is no way you need 180g carb at one time, and that is a fact. The 50g protein, well I guarantee a guy your size doesnt need 50g protein at any given time either.

But if you really wanna use it so bad twice a day (not sure why) then best times to use whey protein are immediately upon rising and PWO.

That's my advice simply answering your questions.

But as for the best possible results, dump both shakes and start eating real food and in the right proportions. There is no time in the day I would ever recommend anyone take protein alone with no energy source of any kind.