I recommend that you use % of weight for your salt, cure, sugar vs 3 TBSP & 1/4 cup, etc. This method is much more accurate.
You need to have an accurate digital scale. Weigh your meat, convert that to grams. Your cure will be 2-2.5% of the meat weight in salt, .25% cure#1, 1.5% sugar. For my taste, 2% salt is perfect, 2.5% was too salty, just depends on how salty you like things. Example, for a 10lb belly there is 4536g. 2% salt is 90.72g, cure is 11.34g, sugar is 68.84.
Mix all together rub all over the belly and place in a zip bag or vacuum seal, turn it daily and massage the cure into the meat. Should take about a week. Rinse, let dry in the fridge on a rack uncovered for at least 24 hrs, this will let the smoke adhere better. Smoke low temp if you can, I do 150 for 4 hrs then bring it up to 175 or so for about an hour until IT hits 160