I would be asking for another scan at 38 weeks and going from there. If bub has dropped percentiles again then induction could be considered more but if bub is travelling well and the placenta/blood flow are all looking good then you could ask for monitoring and go a bit longer.

I had GD in my first pregnancy and was taking about 120 units per day by the end. I had a scan at 36 weeks that showed DS to be around the 50th percentile. They wanted to induce me at 38 weeks but settled for CTG monitoring every second day until I was induced at 39+3. DS was 8lb, so not huge and was perfectly healthy. I didn't want to be induced but at the end of the day I was taking quite a lot of insulin and the stats were a bit worrisome - we didn't want something to go wrong and live with the 'what if's' so we decided it was best for us if we went ahead with the induction.

It is a really hard call and basically all you can do is listen to all the advice and then go with what you are comfortable with.