As an early-career researcher, I would like to get some organisational experience with chairing symposia, and am considering proposing a symposium for my (sub)field, at a major conference of the (general) field, which is psychology. I have the following doubts:
1) How is it best to time the symposium proposal's submission relative to obtaining the full talk details (titles & abstracts) from speakers? Some suggest that the latter can be obtained later once you have the symposium accepted; but to me it seems to make more sense to first enquire among colleagues what a possible symposium theme might be (seeking a convergent theme among everyone's current research keywords), before proposing it. Perhaps, as a mid-point, it's reasonable to just get acceptances from presenters, with only a rough idea for the symposium's thematic "centroid"? Trouble is, the conference I was considering actually requests (as do others) that the full talk details be included with the symposium proposal itself!
2) Organising a symposium is of course peanuts in comparison to organising a whole conference, but I anticipate even that will take a bit of time (negotiating talk topics, handling withdrawals/replacements, etc), so I wonder: alongside my actually enjoying it, and academia being arguably a 'gift economy', is there a real career benefit in having 'symposium organiser at conference X' in one's CV, i.e. are there real points 'scored' with this activity when applying for grants & jobs?