Special Situations Credit Products

Hi all, 

I would like to understand a bit more about the Special Situations credit investing. I am located in London but any input on below from either European aor US perspective would be much appreciated. 

- what sort of debt product are prevalent, what are coupon levels?

- what are common structural features and protections in documentation?

- Which are the largest special sits funds in the market?

I think in terms of IBs that have teams GS is the biggest, followed by DB and Nomura? Am I right?

Any quick reads or videos you would recommend? (I found few good ones in youtube but ther are tons of the maybe I am missing a really good one)

Thanks for insight!