You have nothing to loose by trying it.
I am on <20 carbs a day, sometimes less. I don't keep track anymore because I eat the same things all the time. My ketosticks read 80. I'm not where I want to be with the seizures, but am tremendously improved fro last spring when I started.
I would go for the straight up classic Ketogenic diet to start. You can always go to something less restrictive. If you start with the less restrictive diet, you end up wondering if it would work better on less carbs. I started on the LGIT, and reduced my carbs from there. Keeping track of the glycemic index was too complicated.
Make sure you have enough support. My epileptologist agreed to let me try, and I saw a dietician, but it was obvious that neither of them had much experience with it. The diet was the opposite of what I was used to, but I didn't get any help witheal plans or recipes. You need someone you can call with questions. Online forums aren't a lot of help if you haven't been put on the classic diet properly, and the posts are almost exclusively parent discussions.