I will be of little help other than to say "the numbers don't mean much".
My 1400 gram (?) Rocky's were starting to come apart, and my age and pre-diabetus starting to effect how cold my feet got. I went a little spend crazy and bought a pair of Zamberlan Smilidon's for warmer and still hunting, and a pair of Hoffman double insulated Mountaineers for sitting and deep snow. (felt liner plus 200 grams of thinsulate) I spent more on these two pair of boots than I probably did on all the hunting boots I've bought in the last 30 years combined. lol
Well the crazy priced Zamberlans, which are supposed to be 400 grams of insulation, are much warmer than my 1400 gram Rockys. And they seem to be just as warm as the Hoffman's honestly at a fraction of the weight (but twice the price). The only negatives for me after two years, other than the price and the odd color, is the leather does start to hold water after several days in the snow. (which is not unexpected) And of course they're only ankle high, so not the best for deep snow.
Main point being, don't put much stock in the manufacturers insulation numbers.
And advice is worth what you pay for it, no two people are the same. I work with a guy who can sit all day in a tree stand with un-insulated work boots and regular socks and his feet never get cold.
