I westernized quite early on (around 1520) because I was severely lagging in adm tech and slightly in dip. Was the easiest westernization ever, which was finished in 9 years.
If you want to expand and play that way throughout the game then you have to crush Muscovy, Ottos, France, Austria, England and Castile at some point or another, unless you inherit them heh
Why did it take you so long to attack the Ottos that they became too strong? Once you are allied to Poland and they have Lithuana in the bag you can destroy them.
I will note one (good) change is that the AI won't just put up with your one stack looting their country and will try to kill it, but you can still loot Anatolia while siegeing Greece, just make it a merc because you may have to delete it every once in a while. Still even as a value neutral for you it hurts them badly.
I would have gone for the Otto's first but Venice allied Genoa and Austria was willing to join that war, still, it was Otto's right after that. I don't think letting them get strong is too helpful.
I didn't have accepted cultures and did not face even one rebellion after annexing Serbia and Bulgaria, I also took Dalmatia or whatever that province is and no rebellions there. My income has been huge right from the start, focus on Mil allows for war taxes to be used at will, huge money for you. Now in 1490ish, Serbia is at 0 revolt and 0 autonomy, Bulgaria is very low in autonomy with 0 revolt except for the one Sunni province.
I think Humanism is good when you go a conquering huge tracts of land, like the Golden Horde, but the non accepted culture thing shouldn't be that big of a deal. I never had any revolts except one I purposely got out of the way in Crimea.
My main point is that you shouldn't have money trouble and you don't get revolt risk unless you have wrong culture and wrong religion with nationalism.
I am way behind in diplo tech, on par for admin and way ahead in mil, so I may try to fall behind in admin a little bit to Westernize.
You don't need to be great at Warfare if you are two tech levels ahead of France. Also, you should be hiring 100 tradition generals by 1490ish depending on how active you've been. Don't be afraid of mercs if you want to protect your manpower, but don't hire them if they are a tech level behind troops you can hire, unless they will only be used for sieges.
I did get a huge, huge, huge break in my latest game when at war with Venice (first war), I got an event giving me a 100 tradition general. He lasted until I was at 60 tradition and could hire a decent replacement.