Birdwoman, you have come a very long way and learned a huge amount in a very short time. Well done! Diabetes is a vast subject and very confusing. Even the different ways our readings can be presented add to the confusion. IMO it might be a good idea to try and relax, carry on with your 20g carb programme if you can bear it, and give yourself eg 4 weeks for the dust to settle. If then you still feel that your readings are not good enough, given your excellent dietary regime, you might consider doing as I did and persuading your doctor to prescribe Metformin.
NICE now encourages GPs to prescribe this for pre-diabetics, but probably few GPs have noticed yet. Jenny Ruhl, Dr Bernstein and other writers are all for Metformin (and so am I). If you have one of JR's books you could check that out in it, or otherwise on her site. I was in the position of seeing readings which, while not terrible, seemed less than I deserved given my dietary sacrifices. It was very discouraging. However, having gradually worked up from a very low dose that didn't do much if anything to 2g extended release daily, from the 2nd May I have had a fasting bg of 5.0 maximum, and usually in the 4s. In the previous months seeing a fasting reading of 5 or less was a rare treat that happened about 4 times a month, and quite often it was 5.6 or over, with which I was very unhappy.
There is research showing that Metformin works better if taken early, so the usual strategy of seeing if one can manage without it seems unfortunate. Don't be discouraged by people who say Metformin makes little difference. With bg readings as good as yours, just a smallish reduction could get you where you want to be.