Jamie
By what you are saying of the advents leading up to your whopper hypo, you actually did have warning but alas you didn't note what your body was telling you.. If you had taken a BG reading when you first felt dizzy shopping you would probably found that your BG were either unde 4mmol/l or on the boder line, it wise to carry your meter at all times, and any odd feelings take a BG...
As to the main question, as you've been running higher numbers for a couple of months to kick start your hypo awareness, I think it would be wise to work with your diaebtic team to lower this down to a preferable tight range before considering any dramatic changes to your diet..
As you may create a couple of problems, by maintaining what you are doing at the present and slowly reducing your BG numbers, will ensure that the higher control has done the trick with your hypo awareness... Another problem you might find changing from one regime to another, that lowering your BG too quickly could cause you to suffer phamtom hypo's which can be just as unpleasent as the real ones, and you tend to feel pretty losey until the body makes the adjustment.
It is also possible if you hit any problems, you won't know what might have caused them getting yourself in a right pickle trying to sort out what did or didn't work..
Has I said it might be a wiser mover to hold back a little, lower you control by the means you at present use, then once settled at a lower level then look again at alternitives and where you want to go next...