Hi there,
I'm a mechanical engineer with over 15 years experience in designing, modeling, prototyping and effective manufacturing of different products, ranging from consumer goods to alternative energy systems.
First at all, because you want to file a patent application you'll need to send me an NDA - unless you consider isen't necessary (but I strongly recomend to do so).
Second: just let me know what is about.
Third - as an inventor myself, I could give you valuable inputs about different features of your product in order to avoid patent infringements (but I belive you already made the documentary research rgarding patentability and prior art).
Good poin with wasting time: noone want this. I want to work, you need your product ready, so let's do it.
Anyway, as you didn't provide any indications about your product and work volume, it may be possible to withdraw my bid (I hope not to be in this position, and I belive you appreciated correctly the value of the work required).