Hi @tanghe
Any premium ACF add-on can NOT be included in a free theme. You can learn more about this here:
http://www.advancedcustomfields.com/resources/getting-started/including-acf-in-a-plugin-theme/
It is possible to add a ‘column’ sub field to each flexible content layout so that you can add in each column and specify the width as you go.
There is no limit in ACF, but all servers have a limit of how much data they can save in one go. Please search this forum / google for max_vars and you will find some interesting threads.
Thanks
E
