Do yourself a MASSIVE favour, set it to Iron, now.....Then leave it there (at least until you have a real need to change it to Scenario Author Test).
Doing this will have no significant impact on the actual perceived difficulty (other than artillery and buddy-aid taking a little longer), but it will help you to learn how CM works a lot faster.....I strongly recommend you read this thread (several times) and experiment with the concepts it explains:
PS - Apologies for confusing you earlier.....I assumed you were more familiar with the games and were enquiring about the mechanics of pre-battle contacts/intel settings.