Navigating collaborations as a postdoc
Note: answered before recent edits. I'll clean it up after it settles down a bit. (minor edits made for temporary readability)
In all of these questions, don't try to settle all issues at the outset. Just start a dialog. In the first case, admit that you will need his help on &quot;methods&quot;, but that you hope he is interested in moving forward with you on the topic.
In the (now removed) case of a student suggest that you are aware that there are issues about his ability to commit, but let him decide whether to spend the time and effort.
And in the second case of a remote professor, ask for his willingness to give you feedback and perhaps collaborate on a paper.
But the key is to open the conversation, not to write a contract. While the boundaries need to be made clear fairly early in any collaborative effort, it needn't be the initial concern. And, most important, don't make assumptions about what is possible before you ask.