Reporting on custom fields



I am testing UShahidi using CrowdMap before I install and configure on my own server and have a few questions.

I have created a custom form with new/custom fields which are really important for me. I want to generate reports on the custom field, allow filtering using custom fields and sum up custom fields e.g.

1 - I would like to allow filtering the reports based on a custom defined City field (drop down) just like the way ‘category’ filters by default.

2 - I would like to sum up the value of a particular field across all reports, or all reports in a particular category and then show it on main.

3 - When customising a form and adding new field, is there a limit on the number of values a drop down field can have? I have a very long  comma seperated list of cities which I want to put in the custom field drop down but it gives error.