Effectively doable: 30% tech + 40% absolutisme + 5% Deccan + 10% Mughal mission/event + 10% Tatar mission + 5% age bonus.
But the tech 27 is available in 1760 normally, so at most early in 1745. So to still have the age bonus you need to delay Age of Revolution. It is actually doable, all you have to do is be sure that no province in the world has 30 dev or more, so Enlightnement can't appear (you can have 30 dev provinces if they are not in your capital area).
So start with a Horde having the Tatar mission tree, conquer most of the world, raze all provinces of size 30 or more before 1700. Wait for tech 27, then activate the Tatar mission, form Deccan and adopt new ideas, form Mughals and don't adopt new ideas, activate the Mughal mission/event and bam, you have 100% admin efficiency for 20 years.
Still I think this is massive overkill. And to do it you should roughly have conquered most of the world before 1700. And you lose the -25% CCR from the Mughals tradition to keep the +5% admin efficiency from Deccan.
While having 80% CCR and 85% admin efficiency from 1750 to 1820 is doable with the Deccan->Mughals, whatever country you start with, and is certainly enough for WC.