I recommend used aspect-ratio (serach wiki), adjust mockups a initial ratio , and generate all mockups from a list aspects-ratios like apple IOS aspect-ratio, and for android aspect-radio use actual sizes "like" as : 2:* "small" , 4:* "normal", 7:* "large" ,10:* "xlarge"

I recommend used aspect-ratio (serach wiki), adjust mockups a initial ratio , and generate all mockups from a list aspects-ratios like apple IOS aspect-ratio, and for android aspect-radio use actual sizes "like" as : 2:* "small" , 4:* "normal", 7:* "large" ,10:* "xlarge" ( 3:4:6:8:12:16 scaling ratio recomendation)