I use 4 oz of dextrose(corn sug) in 2 cups of boiled water for 5 gal.
I'd say 2 oz in 1 cup would make 2.5 gal.
or 1 oz (28g) in 1/2 cup for 1.25 gal.
33 g and 3/4 cup for 1.5 gal sounds great, especially if it's worked for you already.
If you're worried about losing some of the water when...