Hi there,
I'm an experienced front/end and mobile web developper and i usually work with checkpoints, for example, i work to reach each point that employer had specified on a document. When i reach it i will receive payment for each point that i complete.
I can build your project with better performance using phalcon framework wish is the most faster php framework, beauty with bootstrap and elements costumization, dynamic content with jquery and ajax calls.
Pm me, we can talk through skype if you want.
Best Regards,
Armando Freitas.