Defining pullbacks using "closes" may not do you much good. Depends on what hypothesis you're testing. Do you yet have one ready to go?
Yes - its basically a reversal setup off of a previous day's high or low. Usually there is a test of the low after the automatic rally after a selling climax but sometimes there is a "V" bottom low instead. I have no plan to take these but I wonder how fast the higher low forms before it takes off again.
This isn't so much a hypothesis as it is something to observe, a "to do". You can choose to ignore the V and focus on the higher low, which is a retracement. Choose your interval, e.g., 1m, determine how high the initial bounce is, how deep the retracement, how quickly and cleanly price resumes the upmove after the test. At that point, you've set up the preconditions for the hypothesis regarding entry and you can begin to look at exactly what entry point the market will sweep you into the trade. Will 1t be enough? Will 2pts be too many? How often is there an adverse incursion? How deep is it, if any? Instead of concerning yourself from the outset with the "close" of the bar or the "low" or "high" of the bar, you may find that none of that is particularly relevant.