If you want to get a targeted responses, hire participants from an online-panel. Attensee is integrated with one of the biggest recruitment service - CINT. Using CINT you can reach over 10,000,000 people from 60 countries who meet your specific criteria.
Please note, that results from your study will be truly insightful after gathering about 50 - 60 responses per tested version of a design.
Try CINT live demo