I also have a self directed checkbook ira which has complex rules including ubti gotchas. Im buying companies with gains made in the stock market. I can let et go, simple is better.
I hold all of my K-1 positions in my Ameritrade account and simply import it to my tax return with Taxact. It puts everything where it needs to go on the return. I would never hold a K-1 in a tax deferred account though. You are correct, that would get very complicated.