So, actually, your argument that eating only fat does not cause a glucose rise is not 100% correct; it may well cause your sugar levels to rise depending on the fat eaten and your own body.
That is an extremely good point and you are completely correct that protein, and to a lesser extent, fat, affect blood sugar levels. The point is that the spike is less pronounced and over a longer duration of time, which is what leads to the fat storage. Say the carbs spike you to 5mmol/l over what you actually need in your body - you've got all this excess energy in the tank that then has to be stored straight away. Then say protein spikes you by 2 mmol/l over what you need (because of the slower breakdown). Clearly there is less 'stuff' that needs to be removed from the blood to be stored as adipose tissue. Simply put, the net result is that your body will effectively 'prefer' to store your dietary carbs as fat, in relation to protein or fat.
With regards to your own handling of protein - obviously I can't possibly comment on what is your body but given that scratching are obviously high in fat, this may potentially slow down gluconeogenesis and remove the spiking in this instance.
Finally, I'm certainly not advocating eating 20 bags of Mr Porky a day! But I will say this - I now tend to eat pork scratchings in place of crisps. I do not exercise a great deal (I know, I'm not happy about that either). I've been doing this for about a year now. My cholesterol level is actually pretty damn good (and not just 'good for a diabetic') and more intriguingly, despite these snacks being supposedly fattening, I've lost two inches off my waist (although oddly, I think I still weight the same). So yeah, I know everyone's different, and also I'm doing a lot more with my diet than just swapping crisps for rinds. But conventional wisdom says I shouldn't be having the results I have. The actual science, however, seems to suggest it's logical.
Obviously this isn't for everyone - but I think you may potentially find it helpful to know that a high fat intake does not inevitably lead to weight gain, and there is an increasing school of though that suggests it might also not be the cardio train wreck we'd expect (did you know the government of Sweden supports high-fat diets as a CVD prevention measure?). It might not work for you. But if you're bored of carrots every night, it might be worth giving fats a go - and simply go back to an older routine if you see the scales going up. That was basically my approach when I decided to reduce my carb intake and eat more fat - the moment I start seeing worse A1Cs, higher numbers on the scales or worse cholesterol, that's when I stop. I'm still waiting for that moment.