Hi Davey! I have similar issues - although even a Ryvita sends my BGs into orbit! I need to put on a bit of weight, and so I snack on walnuts, brazil nuts, almonds - any nuts really except cashews. They have a slight impact on my BGs, but are full of good fats. I also eat avocado as a filling snack as, like you, I can't eat fruit very much - it also helps with weight gain. If your weight is an issue, you need to add full fat cheese, milk, yoghurt etc to your diet, but you'll have to balance that against any cholestorol issues. You'll need to get medical advice before doing that - and probably give up smoking.
Good luck
Smidge