Gasoline Fumes mentioned getting a spacer from an older Civic to put in place of where the rocker arm had been, to cover the oil hole so as not to affect oil pressure. I was trying to find the spacer, officially called a "shaft collar," when I realized that my car came stock with them. A trip to the junkyard got me 4 more for $1.
While there, I compared the collar to the rocker arm to find that the collar was not as long. At first I thought it wouldn't work and would have to make a custom length part. Then it occurred to me that I could use the spring as a variable and swap the pieces around. My focus was on removing rocker arm B. In doing so, I replaced the rocker arm with the spring. Upon returning to stock, I realized that the spring was therefore not blocking the oil hole as Gasoline Fumes had suggested. I couldn't think of any other way I could have done it apart from a custom piece, so I didn't feel bad.
But it hit me in bed last night that if I would have removed rocker arm A instead, I could have simply put the collar in place of that, with the spring still being the variable, taking up the extra slack. Ugh. I've never been good at puzzles.
So I don't know if that caused any issues or not. Indeed the whole rocker arm assembly seemed a lot more oily when I took it out the second time. But whether that affected the pressure or caused the pinging or any issues, I can't say. Maybe it had no effect at all.
Stock setup:
3v:
Thanks to Gasoline Fumes for being the pioneer and giving me the courage to try something like this, as well as to everyone else for your advice and help.