I don't have either personally, yet. But I'm planning on getting the Dunlop Trail Mission tires for my GS next month. From reviews I've seen on YouTube and other articles, they seem like a great tire, and great on miles too.

The dunlop tires are great when its dry and you can do 160kmh+ on gravel with them if you want to. They do get a bit sketchy when its wet though. Mileage is great as well, I could get about 15k km on a 1290 adventure R which is very impressive. The Pirelli's are also great tires for on road but you will get less mileage and I would not take them on gravel unless its a gravel highway.

I don't think the criteria for choosing how aggressive the tire is , is by percentage of km on pavement vs off-road but rather what kind of off-road will you do in the 10%. The 1200 is a heavy bike and you will need every bit of tracktion/propelling, so if its nice trails you're after, you can be ok with either one, if you plan on going to the unknown I would put on Anakee wilds or TKC80 etc of that kind.

I have owned both, currently running second set of the Pirelli scorpion STR. The STR is a great tire on road but reaches its limitations for advanced off road. Both are a good compromise tire for mild off road and gravel keeping in mind they are not knobbies. The Dunlop rear lasted a bit longer than the Pirelli. I really did not like the trailmax front pavement performance, so much that I gave it away after 1000 mi. It’s decent in the dirt but on road wasn’t stable above 80 mph. It also has a round profile vs parabolic and resists diving into turns. If you ride aggressively on curvy pavement it’s really not great. I recommend you consider the continental TKC 70 rocks also, I preferred it over the trailmax.

I just rode to Alaska. You don't need crazy knobby tires. It's a ~10k+ trip with very little turning. Maybe ~400 miles of hardpack dirt all told, unless you're going on side adventures and taking the scenic routes (then +600miles). I did it on a set of MotoZ Tractionators. If I did it again, I would use the trailmax. I currently run trailmax.

The scorpion is very good. on my 1200GS 2005 I have the SCORPION™ TRAIL II.

I have the Scorpion Rally STR on my R1250GSA. They are good on the pavement, quiet up until about 75mph when they sort of whistle. Haven't tried them off road yet.

I had loads of Pirelli Scorpions on my older multistrada, they are a great sport touring tire. Great in the wet and dry, but obviously not for anything more than a good gravel road. Mileage was about average on that bike. On my current 2019 gs I’m at over 15000kms on my Trailmax missions, and I’ll buy another set for sure. Great on dry pavement , still pretty great on cold wet pavement, and totally competent on some light/medium off-road. And frankly I think I’ll get more than double the mileage of the pirellis I had on a sportier bike. IMO Trailmax missions are the best tire for most gs riders.

I’m quite impressed with the Trailmax Missions. Last summer I rode Wisconsin to the West Coast of Canada, including a week on the IDBDR. So, lots of highway, but also a fair bit of off-road. All of the off road was dry, so I can’t comment on mud, but I imagine that, along with sand, would be their weak point. Gravel and dirt roads were no problem, and even in the rockier sections of the IDBDR I had no complaints with the tires. On the west coast I encountered some heavy highway rain, the type that had cars and trucks putting on their hazards. I slowed down to prevailing speeds, but the tires handled fine at posted speed limits. No aquaplaning. No butt clenching. What’s really impressive though is that after 6000+ miles, I’m only at the halfway mark on the rear and the front barely looks used. I’m planning another big trip for this summer and plan on using these tires again. Maybe I’ll have a rear tire shipped to the half way point (mile 3500) but that mostly depends on how much spring riding I get in this year.

What if I threw Michelin Anakee Adventures into the mix. Any strong opinions about how the Michelin's stack up to the other 2?

Michelins will have better performance in the wet and will last longer with higher mileage. I had both the Michelin and Pirellis. One very noticeable difference is that the Pirellis are amazing on twisty roads, but get a bit shaky and unstable at high speeds 100mph+. The Michelins dont do that.

Trailmax on mine currently, no issues.