I am interested!

Hey, you are correct that "no" is a group 4 indicator and the correct translation of it is negating the necessary condition. However, in the example you gave "no action is based on good intentions are justified unless they also result in success" as you also mentioned contains group 3 negate sufficient indicator "unless". As a rule of thumb, where there are 2 negations, they just cancel each other out, therefore, you can just diagram the statement as justified -> successful which the contrapositive is going to be not successful -> not justified. Hope it makes sense!

How do you negate the ac(c)? some replaces not all?