Ian, I can't give you any figures but I can tell you I lost a lot of weight etc and was convinced I had diabetes. I 'confirmed' it with a urine test that went the darkest possible colour (I 'filched' one from the hospital loo when my daughter was in labour!)
Not going into detail but I didn't go to a doctor, I did mostly try to do what someone diagnosed with T2 would be told ie I (mostly) ate a healthy diet (low GI ), I exercised.
This was three years before I went to a doctor following more weight loss accompanied by a total lack of energy ( I knitted 3 jumpers in about a month, I didn't knit before and haven't since!.
To get over the inactivity, I forced myself to try a mountain bike ride, ended up gasping for breath .My husband thought I was having a heart attack,. Got back to the car breathing became normal again. I found a GP , tried to explain. To his credi, he sent this very skinny, mad Englishwoman who seemed to think she had T2 for a fasting blood test. Had it next morning, results faxed to the doctor and I ended up in hospital for 10 days!
Looking back, I think that after my first bout of weight loss there were sufficient beta cells to cope whilst I ate and exercised normally. They were though still being lost, slowly. Eventually the critical point came again and by this time far too little insulin was being produced. ( c peptide was very low) and I hadn't enough insulin to keep fasting levels at anything like normal. (mid 20s at diagnosis) My Hba1c though wasn't sky high, it was in the 7s.
The gradual loss of cells was 'normal' for LADA . It seems to take longer in older people than younger (though there are case labelled LADY of LADC (latent autoimmune diabetes in the young/children) . As it is caused by an autoimmnune reaction it's going to happen whatever you eat.
Your lower carb diet may mean that you can avoid insulin for a while (until you have insufficient to deal with basal needs) but that is a personal choice Normal peoples glucose , is not by any means static, it moves up after meals and their body releases insulin to deal with it. If you can't eat a few berries at breakfast then you don't have sufficient insulin function to cope with normal requirement..
. People have very good outcomes when they use insulin sensibly to control their glucose to reasonably good levels (the DCCT trials didn't find anything like the same benefit for reducing HbA1c levels below 6.5% as they did for reducing levels below 8%)