Wow. Congratulations on actually trading these things (which I have yet to do) and especially for being profitable.
Although you now officially have more experience that I do, I feel compelled to mention three more things that I recall reading on this topic, just because I'd feel a bit guilty if not knowing these things screwed up your trading.
1. I read somewhere on distresseddebtinvesting.com that, on the day a company files for bankruptcy in the US, it is supposed to file a Statement of Financial Affairs ("SoFA") which usually has a ton of information that may be able to help you estimate the recovery value of its debt instruments. I believe you can pay pacer.gov to retrieve this filing for you, or perhaps you could use the paid service that distresseddebtinvesting.com runs if you're doing that enough.
2. I don't recall how I came to believe this, and I'm not 100% sure about it, so you definitely should verify it, but, my understanding is that, by convention, the price quoted for a bond that is not defaulted is a base price to which you need to add a linearly (I think) pro-rated fraction of the next coupon payment. So, for example, if a bond makes a $2 coupon payment every January 1st, and you're trading on April 1st, then you need to pay $0.50 more than the quoted price to buy it. However, defaulted bonds are quoted just as a total price, with any defaulted coupons still attached. I think that this difference can be substantial, because a company will often file for bankruptcy on the day some payment is due.
3. As mentioned in a fictional example in Larry Harris's Trading and Exchanges: Market Microstructure for Practitioners, if you're dealing with a network of traders from whom you have to request quotes, such as the bond trading network that TD Ameritrade uses, always ask for both the bid and the ask prices without indicating whether you intend to buy or sell. Obviously, if you don't own at least one of the bonds, the TDA representative will know you intend to buy (since TDA does not let you short them), but ask the TDA representative not to reveal that but instead to just request quotes for both sides of the market.
Regarding potential plays to consider, I was a bit surprised that I couldn't find bonds for Sports Authority on finra.org.