Can someone tell me the rate between 1 lb of dextrose and that amount of cups that is? I have it at home in a book but I am at a friends brewing at the moment.
The problem there is that dextrose can be compressed a little in the cup so weight is not constant using the cup measurement.
I believe the 4 oz that usually comes with kits is comparable to the 3/4 C recommended for priming.
I would go with 4.25 oz (by weight) for 5 gallons of beer (gives 2.4 volumes of CO2 carbonation).
I agree - you should not measure sugars by volume as you could be way off!