ios - Am I using AutoLayout correctly? (Screenshots inside) -

so i'm designing layout app , have difficulties adjusting layout iphone 4. example @ these screenshots:

as can see barely fits on iphone 4 , iphone 6 has blank space on bottom. using auto layout incorrect or intended behaviour?

i struggled not being able make text fields smaller fit iphone 4 screen in layout.

help appreciated!

1. if embed views in uiscrollview (with autolayout set), content visible(scrollable)
2. if use size classes, can set specific ux iphone4