I am in the same position, however, I am not enamoured of the Gi/GL method. This is specifically because the GI centers on data collected using young, fit non Diabetic subjects. And because even when one has worked out all the numbers one's individual reactions to foods means that there are just too many variables.
Here is what I am doing to maintain my weight (a work in progress).
I have raised the amount of healthy fats again and I have raised the amount of protein in my diet. As fats will have virtually no affect on bg and protein a much lesser affect on bg than carbs my (bg) numbers have been stable throughout this period. I am not losing weight as I once was. I am in the unusual position of not being able to increase muscle mass but I am endeavouring to protect lean mass. You should be able to increase your muscle mass (if you are physically able to do so) with resistance excercise of some sort.
Hope this helps but just a note, it takes longer to add weight with protein and excercise than it does to lose weight on low carb.