You don't see the bar progression, but from divided to -> mostly loyal, you just do 1 loyalty, then from mostly loyal -> generally loyal, it generally needs 3 boosts/purges. Going completely loyal is useless in the long-term, mostly just aesthetic.
Generally loyal Prussian bulwark is more effective when you ban the SA, though I recommend you just do "boost loyalty" 2-3 times, then switch to recruiting, which gives 20k more men per recruitment, making them more effective when you try to arrest and deport Hitler, or when the SA disrupts your rallies.
Speaking purely from experience, I actually don't know the metadata.