This is not a very long list! Much of my thinking about geoengineering, and I think about it quite a lot, is still in a formative stage. The following however, I think I can say I am unlikely to change my mind about.
1. Geoenineering research is vital, and should be undertaken honestly and, as far as is possible, without advocacy (or, at least where there is advocacy it should be transparent). This is as true for those advocating a moratorium on geoengineering as it is for those in favour of deployment.
2. Advocacy of geoengineering research does not mean advocacy of geoengineering deployment.
3. Geoengineering research must not, under any circumstances, be used to undermine 'the right thing to do' which is to reduce our dependence on carbon.
I am working on an analogy (as I haven't found one yet that strikes a chord with me - lifeboats, airbags etc). I think my current best effort (although upon browsing the web I see has been mooted in many places online already) is methadone. There are several interesting blogs on this (with the caveat that I do not endorse their opinions, especially those from the comments section beneath) - a good starter is this one...
I think the reason I like the methadone analogy is that it conveys the bleakness of our current situation and does not paint geoengineering as a silver bullet, some sort of panecea that will solve all our problems with one simple flick of a switch.