Question: I've seen a lot of different topics and suggestions on aligning and inputting buttons/text, but the ways I've seen seem kind of risky.

What is the optimal way, for example, to add two buttons, stack them together, and have them be 10% from the bottom of the screen, and centered horizontally on all devices?

Answer: 
Learn Auto Layout if you haven't yet. Use constraints for achieving the following:

> 
> 1. For centrally Horizontal on all devices: Use Center X with SuperView.
> 2. For having them 10% from bottom, use multiplier value say **0.10** .
> 
> 
>
Your best bet is to use [Auto Layout](https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/AutolayoutPG/index.html). It takes a bit of learning but once you get used to it you can add constraints pretty quickly and easily in Interface Builder. I can't recommend any particular guide but there are a lot of good ones to be found with a quick Internet search.

Here is an example of constraints that seem to be what you are looking for:

[![Auto Layout Constraints](https://i.stack.imgur.com/JVDZX.png)](https://i.stack.imgur.com/JVDZX.png)
[![iPhone 4-inch Portrait](https://i.stack.imgur.com/K9SaD.png)](https://i.stack.imgur.com/K9SaD.png)
[![iPhone 4-inch Landscape](https://i.stack.imgur.com/YmzIQ.png)](https://i.stack.imgur.com/YmzIQ.png)