There's a safer and simpler way. Inform the manufacturer about your proposed changes. Because apart from the design philosophy and software and hardware access the manufacture has a global customer reach and incidents. So if you want to change something in Argentina that may have been already done in Korea and ended in a screw up. Armed with FCOM, FCTM no one is in a position to make their own procedures. There's famous incident of Jetstar Australia and two other Airlines changing FMA call on GA to only after gear up. The captains stopped short of TOGA and waited for gear up to check the FMA. Copilot waited for positive climb to put gear up. The aircraft remained in approach and worst case it came down to 14feet before they pulled up. All returned to previous procedure. TOGA first FMA to confirm transition to GA then everything else.