Build a stable WebRTC application

We have already developed a WebRTC prototype application that works. This Application is meant to do the following: We have 1 broadcaster and we have 1 watcher. The stream should be HD: starting from 720p up to 1080p, depending on the watcher's device. On this stage we only care about 1 broadcaster and 1 watcher. In the next stage we would like to add some watchers (1-5 additional watchers, but not much more). But we experience some issues when using different PCs / devices. On this stage we do not yet understand exactly what causes these issues. Issues we experience: On some machines a video resizing is happening On other devices the video size / resolution stays constant but there are moments when the video freezes. And yet on other PCs the frame rate (fps) is way under 30 although we define a minimum of 30fps in our media constraints. We need an experienced WebRTC developer that can act as a consultant by looking over our shoulders and answer some questions, but who also can go into "hands-on" mode and start coding. We need someone that can really track down these problems because we want to exactly understand what is happening and why. Someone who can look into the whole architecture: Hardware limitations, Internet bandwidth, WebRTC API etc. would be optimal. The ultimate goal is that these issues are fixed. Once this project is successful we would like to keep the collaboration and talk about scalability (but this will be another project).