Must admit to being surprised by someone who's undertaken DAFNE asking questions, I've done DAFNE myself...
You need to be extra vegilant with monitoring, the decrease in carbs will mean less insulin for carbs, which you already know.. But you are increasing fat and protien content of your foods, working out ratio's for these two can be a lot more difficult...
Has you will need to determin wheather, you best advantage for control, will be increasing your basal or the actual bolus to cover what you are eating...
Going extrem low carb can be difficult using just background and quick acting insulin, so you may need to add a 3rd anulog insulin one that you inject 1/2 hour before eating certain meals to get the right coverage/balance, which can't be achieved using the 2 insulins adjustments...
One of the thories behind the regime, is that burning fat as a fuel is slower, so you avoid peeks and troughs in control, but this can be a draw backs, yes you can tight control at lower limits, but you may pay the price with losing your hypo awearness, and there are times when the engery transfer from fat to fuel, isn't going to be quick enough so you will still may need the backup of fast acting carbs...
My best advice is to reduce slowly, even out carb in your meals first, then reduce monitor all the way, to find patterns, then ALWAYS keep a very good supply of fast carbs on you at all times, as you could be at higher risk of hypo's... Also identifications, that you'll diabetic etc just incase you start becoming hypo unawear...