I was more asking about how to sort out help offers after I've received them. I'm not entirely new to ROM hacking, but I've only worked alone before. I've received offers to help for things in the past, but was never sure what to do with them, how to tell how genuine they were, whether they would actually be helpful, etc. So for the purposes of what I'm asking, I'm assuming I already have something to show, and there are people interested in helping, which I wasn't clear on in the OP.
I'm currently on the team working on the Deadpool hack of Ninja Gaiden. Danger X asked if I wanted to join after I solved some problems that he had asked about in a thread on this forum. I know another of our current lead team members started out by showing the team some graphical assets that he had created specifically for the project. If somebody is both willing and capable of helping, they should be able to show you samples of their work/abilities. If you have a specific problem or area in which you need help, I'd ask about it and see whether they could actually give you something. One option would be to make a thread about what you need in the help wanted section, and if somebody offers to help you via PM or on another forum, you could just point them to the help wanted ad. That way if they don't work out, other people could see the ad too and you won't have wasted time waiting on somebody unknown.