I won't do that :) I stopped working on the spec the moment I handed it down to coders, and my total time spent on the spec since then is around one week. When the spec is written well, and you simulated all important situations in your head before encountering them in the wild, you actually don't need much extra time.

There's almost no tinkering happens on the app right now. I'm fixing critical bugs and smoothing out rough details that manifested after months of my dogfooding.

Regarding the desktop solutions: yes, going native would be perfect, but that is not feasible for a 4-man team. We'll go with Electron or Xamarin or, less likely, Qt - we haven't decided on the exact technology yet.