personally i would eat 200 - 300 under maintenance and try and get as close as i could to my macros. all depending on my tdee though, if im doing a lot of stuff on my feet then i would probably just...
the problem with gainer shakes are that they for one taste awful, are pricey and are like effing 150g of product to chug down. youre better off with some calorie-dense food. find out whatever...