Very interesting comments, Andy. I don't have any experience with TKS, so I'm really happy to benefit from yours!
My only understanding about all this is based on discussions with my AME when I asked him if we could "FIKI-ize" a plane equipped only with inadvertant TKS. He consulted TKS on the issue, and he told me that it involved a lot more than adding a second pump or a heated stall-warning. It seems that the TKS panels themselves are in some way different, and I'd be looking at a $40k fee to do an upgrade. I'm sorry I don't have the specs, but I do trust my AME, who has been an authorized Mooney mechanic for a long time.
I acknowledge that there are limits to what you can fly in, whether you have no de-icing, inadvertant, FIKI or a hot-wing. What scares me a bit is that I won't really know what the limits of the aircraft are until I'm actually doing an approach in them. So, chances are, I will be overly cautious until I figure out how it all works. But I do hope, with FIKI, that at least I'll be able to fly on those days when there's just a bit of light known icing from 2000-4000 ft with sunny skies above - which is pretty much 50% of the days of the winter around here.
While I'm intrigued to hear that you say there is essentially no difference between inadvertant and FIKI, I'm still going to have to draw the line at FIKI, just because I know that's the answer my insurance company would like to hear. Perhaps when I have more experience, like you, then I'll be more flexible in my position on this.
However, when I do finally get my plane, I'll be coming to get your comments about how I should and should not be using my TKS. Your insights are priceless!
Thanks for the ad, Scott, but I'll have to hold out for FIKI unfortunately.