"Subtle" is a strange word to pronounce in American English. The 'b' is silent and then the 't' becomes an alveolar tap (represented as /t̬/) because it is now between a vowel sound and a syllablic /l/.
Since the alveolar tap sounds like a quick /d/ in English, the word "subtle" rhymes most closely with the word "cuddle" in the list above. It would also rhyme with the word "shuttle."
British English does not use the alveolar stop in this sequence of sounds, so, in British English, the word "subtle" would rhyme with "shuttle" but not "cuddle." Oh English, why must you do this to us?