Warpspeed you're a legend, thanks for all the info. The idea of changing pipe housing had crossed my mind earlier but for now i'd rather leave my original AFM just that, original. If i get another one in not so good condition i'd try it for sure.
Since looking on the net, like here (those vortex ones seem interesting), and discovering a bit more about how hey work, i've come to think that fiddling with electronics wold be a more elegant solution.
What do you reckon about the ease of altering the thermistors to ones with a different gradient?
Edit: Speeling