I would keep all twenty on the list. The scan you did was for the minimum heart rate to give you that calming effect and find the frequencies that relax and calm you more yes? so if you wish to shorten, uncheck the ones on the bottom, and leave the top ones. I wouldn't shorten though, I would just keep the whole list, as it takes time to scan, and I want to make use of all the ones it found. 20 out of 80k is not very much.
It is all in your application and what you are trying to achieve.
If you are seeking "Lowest" BPM, then the list starts "the top"with the lowest, so keep the "top".
I see you were running graded on hypertension. still applies though if you wish to get rid of some get rid of some, since you are seeking the lower BPM rates, get rid of the higher rates. higher in the parenthesis that is ().
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