I haven't done that kind of testing for a long time, but I did do it during the first year when I was still quite insulin resistant. I found my biggest "problem" low carb foods were:

Overcooked/pureed vegetables in my LC soups, especially when having the soup stand-alone or before a meal. I was eating carrots in limited quantity at the time. My BG did little after eating raw veggies (including carrots). But veggies cooked to near the texture of baby food spiked my BG big time. Same number of carbs in the veggies, but completely different BG reaction depending on how they were prepared and what I ate them with. Having that veggie soup after a meal of mostly protein and fat was far better than having it first.

Carbs in sauces really spiked my BG. A 3 carb serving of stir-fry sauce tossed into sautéed meat & veggies seemed to suck straight into my veins. I had a far bigger BG reaction than I expected for so few carbs.

After these experiments I changed how I ate. More raw veggies, far less soup, and rarely have stir fry with anything other than a little soy sauce.

My insulin resistance did eventually improve. After that happened my BG reaction to such things has tempered quite a bit. I stopped getting readings above 150 to 200 from a 10 to 15 net carb meal. In fact it rarely cracked 100 after a meal. So I stopped checking my BG except for the occasional FBG.