I have found it easy to convert to cure #1...
Let me give an example.....
I make up, ahead of time, a cure for my fish......
I usually make up enough for 50#'s of fish at one time, and have it stored in an air tight container for later use....
I have found I like about 2% salt and 2% white sugar for my salmon sooooo...
50#'s(454 grams X 50 = 22,700 grams) of fish and 2% salt = 22,700 x 0.02 = 454 grams of salt
2% sugar would be the same.... 454 grams of white sugar
154 Ppm nitrite in the fish would be 22,700 x 0.000154 = 3.5 grams of nitrite / 0.0625 (% nitrite in the cure) = 56 grams of cure #1
454 + 454 + 56 = 964 total grams of stuff that will properly cure 50 #'s of fish....
For each 1# of fish(454 grams), you would then add (964 / 50 = 19) 19 grams of your custom mix
Thoroughly mix before each use... additional spices can be added to the fish to adjust personal flavor... I use a non salted spice mix like Mrs. Dash to kick up the fish...
I sprinkle on the proper amount of mix and spices and let it sit on the fish, it a plastic tub or zip bag for a few days.... rinse, dry, form a pellicle and smoke...
Anyhow, I hope that gives you some insight into what can be done...
Dave