No we don't have a target JA, but generally we don't have carbs at all at dinner if we have had them at lunch and vice versa. We never have bread or rice now but still have new potatoes and spaghetti occasionally, but only about 100g between us. So a cold meat and jacket potato meal has become cold meat and aubergine parmigiana, for example. If we feel we have had too many carbs we cut them out at both meals for a day or so. We always have a slice of spelt toast and our own muesli at breakfast, unless it is an egg day. We started off with just low GI and ate stuff like bulghar, quinoa and pearled spelt but have reduced carbs even more as we got used to the diet.
We find we can't really eat sugar at all now as it just tastes too sweet. OH found that he was putting a couple of pounds back on recently so he cut out summer fruit (this was hard) and the weight came off again. Lots of trial and error, but I think you do develop a sort of sensitivety to what feels right after a bit.