[masch]

Hi Toolusr,
I'm working in the same field as you do - in Software Development - and I definitely struggle with contexts for quite a while for the same reasons. I usually start off with a thought or an idea which needs to ripe over time and as you stated migrates through different stages which usually don't refer to physical triggers but could happen anywhere or anytime, be it the couch, under the shower or sitting in the garden watching the children play. Only at some point I really need to sit down at the desk with a physical context (e.g. computer), take some concentrated and focussed time and do writing or programming tasks.
So, for me, your approach is not over-thought but reflects reality pretty well. Even more, the physical contexts for most of my tasks are not necessary as long as I find my iPad, iMac, Laptop or a paper and a pen to get going, usually no matter where it happens or when, as long as I'm in the right mental state to drive things forward.

Thanks a lot for delivering a shortcut and save me from analyzing my own 'cow paths'. The only thing I might change is the colours of your contexts, though ;-)