If you are 75% good, your counterpart will be 75% evil.
If you are 99% good, your counterpart will be 99% evil.
What do you do if you meet your evil counterpart?
If you are 75% good, your counterpart will be 75% evil.
If you are 99% good, your counterpart will be 99% evil.
What do you do if you meet your evil counterpart?
Only if successfully completing experiments is itself good or evil. The question stipulates they are our moral inverse, not opposite in every way.