For a 2kg belly, you would use 5gr of cure (.3gr sodium nitrite + 4.7gr sodium chloride), PLUS 35gr Kosher salt, PLUS 20gr sugar. That is the %2 salt recipe. 2.5% salt level would use 45gr of Kosher salt.
The 1% recipe would use 15gr of Kosher salt, but I'd make sure it's ok to use that little...