Climate sensitivity should be an advanced undergraduate topic. Prerequisites include: 1) basic theorems of rotating and/or stratified circulations 2) planetary energetics 3) atmospheric circulation 4) ocean circulation 5) glaciology (in two separate equal parts: sea ice and land ice) 6) paleoclimate.
So I think about two years of sequential (3 classroom hours per week plus six to nine hours of concentrated effort) courses (or of course, equivalent attention in other contexts) is enough to start forming your own opinion about physical climatology. Addressing the sensitivity quantitatively before describing the system seems to me a pointless activity.
Unless you consider yourself the equivalent of an advanced undergraduate, what you have about climate change is not an opinion about science, it is an opinion about whom you trust about science.
This applies equally, of course, to me and the many things I myself know little about.
On matters where I have no depth, but where decisions are needed, my opinion is about whom to believe not what to believe. This is as true in day-to-day life as it is in political opinion at the grandest scale. Trust is the currency of civilization.
Trust in people who deserve trust and not in those who don’t. Or fail.