So, i finally did it yesterday evening (well, rather night, 3 hours sleep, wanted to finish this!)
Everything not sandy yellow in asia is a vassal.
As you can see there is still plenty of time left, and i already head 490 provinces at 1700 but i made a stupid mistake and accidentally released Ming (missclick, wanted to release some indian minor because OE, you can see the bump in the province graph) as a vassal before i had the 500
So, my general strategy was:
Stay Muslim (as you can see, i haven't westernized yet), use Ottomans as your warbitch early a buffer later, cut off Russia and the colonizers. All worked out fine, although Portugal somehow got 2 islands in Indonesia.
Ideas:
Innovative first, the merc bonus and we reducement really helped in the beginning, otherwise i would have had to take DOTF because i was at war constantly, unless i wanted to start annexing, so i saved practically 15% per tech (with increased innovative which always popped up when needed). It also helped to always stay 2 levels ahead in mil tech, thats better then any mil idea set in the first 100 years. Im still on par with Europe in Adm and Mil tech, dip of course not, spent it all for core returns.
Diplo is a no brainer if you want to have vassals
Exploration also, you would have to conquer eastern europe otherwise, wouldn't work while staying muslim.
Expansion, same reasons.
Adm. for the core bonus only. Would have also been a nice first, but i think this order was better because central asia is just full of cores to return. And thats practically all you do in the first 100 years. I only started coring in Africa and Egypt especially.
Aristocratic for the Diplomat only, as diplomats where the only constrain to my midgame expansion.
Offensive and quality last, so i can Unify Islam in the last 100 years. Spain will be a tough nut.
Bottom line:
OE's a bitch
I don't think it is even remotely doable westernized. You would need a coring bonus like the Ottomans, which you don't have. I didn't do the math, but i guess it's not even theoretically doable if you want stay under 100% OE most of the time, which you want. Otherwise you will fall so far behind because of the bad events, and you will run out of dip points before you run out of adm points.
Everybody is scared of you once you have the biggest army in the world. The only one who ever attacked me was oman, and that was 2 years in. They got vassalized outright.
Not that hard once Russia is cut off and the Cape colonized. I dowed Russia, seized their eastern colonies, then peaced out for a shitload of money.
Offered loans that will never be payed back are your friends. Easy way to get distant horde vassals with cores all over without eating a stab hit.
Could have done it by 1650 i guess if i hadn't played on speed 4 all the time. Got pretty boring

So yeah, you need all of asia plus half of africa, i am at ~560 once i annexed my vassals
p.s.: Am i the first who did it? I know there was a time you apparently got the achievement for clicking the start button... Gonna fetch me some Falafel in today's work break anyhow
