Here is another excerpt of information I posted about PWCG for those who may not be familiar with it:
For anyone who hasn't tried PWCG but has RoF and is looking for something more, it is a must have. If you want shorter "instant action" type missions, but with career tracking, then shorten the mission distance in Advanced Config. If you want longer more realistic missions (like me) then increase the mission distance. If you want some "no contact" missions in the mix, never knowing if or when you'll make contact with the enemy, then move the percentage chance of contact to 70 or 80% instead of 100%. If you want to change the skill level mix of the AI pilots you face, then change the random skill level generator percentages. If you aren't happy with something about the missions you are flying PWCG lets you change it. I'm guessing there are over a hundred different mission parameters you can change in Advanced Config. And of course there is a Simple Config for point and click changes that can be made in just a matter of seconds. PWCG is incredibly flexible for both beginners and advanced users.
In PWCG for RoF I've had missions where I'm rolling off the field with bullets kicking up dirt all around me and wingmen on fire as I take off during an attack on my field. And I've had missions where I thought I would have no contact while taking out a bridge in an R.E.8 flight, only to be hunted down after a 90 minute flight while I'm trying to set down on my field. I've flown 3 hour Gotha missions into England, sometimes not intercepted, sometimes intercepted over England, and sometimes hunted down on the way home over the channel from squadrons patrolling out of Dunkirk (you can use time acceleration to turn them into 2 hour, 1 hour, or 20 minute missions).
Or fly Handley Page bombers on night raids into German territory only to be intercepted by Albatros night fighters from Kest squadrons coming in at you out of the dark. Or fly for a British Home Defense squadron or a German Kest at night trying to find the Gothas or Handley Page bombers in the night sky. When the big bombers reach a major target and the search lights come on its an incredible light show (whether you're in a bomber or in a fighter hunting them). The stuff that can happen in a PWCG mission pretty much blows my mind when I really think about it. Its absolutely white knuckle. If you haven't used PWCG with RoF, you really haven't played RoF as a single player. PWCG showcases features you didn't even know existed in RoF. Oh, and you can also fly in the role of a traditional hotshot fighter pilot.
Edit 1: Another important feature in PWCG is the ability to set the density of ground and air units to tune the mission size to the abilities of your computer.
Edit 2: PWCG uses an internal system generated "dice roll" for probability percentages. For instance, when you adjust the skill level of AI pilots to say: 25% Ace, 50% Veteran, 25% Rookie that means that overall you will face 25% Aces on the average of say 100 missions. It doesn't mean that on every mission you will face 25% Aces. You could run into a squad of rookies, but on the same mission you may run into a squad with a couple of aces and two veterans. So you can control the overall big picture, but on any given mission, or any given encounter within a mission you won't know for sure who you're up against. Of course, you can skew the percentages to 0% Aces and 0% Veterans if you only want to fly against Rookies. But any reasonable spread of percentages makes things fairly unpredictable but with a slant towards the percentages you have specified.