Solution:
You will have to add custom jQuery/Javascript code to count number of checkboxes options checked/selected and based on that you can limit the number of checkboxes allowed.
Will using Toolset on both dev and main site count as 1 or 2 site licenses?
I want to keep the auto-updates going on dev as well.
Solution:
You can install the Toolset Types plugin, and click the link "This is a development / staging site", so you can still get auto-updates in the development website
