What is the easiest way to export Field settings into a .install file?
There are some useful resources on how to do this. And you dont have to use Features.


Exporting and creating field definitions in Drupal 7 blogpost by Joel Stein
Drupal 7 export content type and fields blogpost by Kristian Nissen


Features is great if you understand what it's doing (calling Field API in an automated fashion and exporting definitions). You can use the Field API to define, create instances, attach fields to entities -- and then remove them all module uninistall as you need.

The easiest way for me to do this is look at the functions in the link above and use var_dump() on $field or its $settings after you make it using the Field UI. Then just use the appropriate Field API call like field_create_instance() to wire these var_dump'd arrays into your modules hook_install(). So i'm saying dont create the arrays by hand, create them in Drupal and just copy an export to your code ...