Good call!
https://www.lexico.com/grammar/these-or-those
These/those are the plural forms of this/that, and behave in the same way. As a determiner this is used to identify a specific person or thing close at hand or being experienced. As a determiner that refers to the more distant of two things near to the speaker, or to a specific thing previously mentioned.
For example, in context of the sentence:
Sonny has many qualities worth recognizing, and the purpose of this letter is to point out two of [these/those] qualities.
These would be best.