I may be doing some second shooting with an established pro in my area. We just did one, as a trial, and it went well. I think we agreed upon a price that is around $33 per hour, based on a 15 hour wedding job. The photos are theirs, to use and sell etc, but I'd have to ask again, if I would be allowed to use them for my own promotion. I think she said that, in the past, they didn't allow that (or they paid less) but I think we can come up with an agreement that is satisfactory to everyone. I think the idea of not posting them before the client gets then, is a good one. I would even add a logo, label or watermark, to specify that I took the photo while working for their company.