For sure blood glucose response after eating is not simple. Alcohol can result in lower levels. Also, consuming fat with carbs can result in "the pizza effect", where the spike in blood glucose levels occurs later than is normally expected.
I would highly recommend avoiding potatoes. They are pure starch (i.e. carbs). So, if you avoid potatoes (and other starchy veg), fruit, flour (you've cut out bread and pasta, but need to cut out everything made from flour), rice, and sugar, you will likely not see spikes in blood glucose. If you do, you'll need to review what you've eaten and figure out what caused the spike.
Personally, I try to avoid going above 7.8 at any time as that's the level above which organ and nerve damage is supposed to occur.
And fats shouldn't be restricted, but should be in the form of natural fats (from animals or plant) that have been minimally processed - so avoid refined veg oil. If you are going to restrict carb intake you'll need to replace the calories with something and natural fat is the best thing to have instead of carbs. Your protein intake should be about the same as it was on a high carb/low fat "healthy plate" diet.
Hope that helps.