High, front vowels have a large F 1 - F 2 difference. Low, back vowels have a small F 1 - F 2 difference. Our understanding of how we perceive vowels is incomplete. Opposite is true of short duration vowels. Within limits, formant bandwidth is not a perceptually important feature.
Nasalization increases bandwidth and reduces distinctiveness of vowels.
Formant amplitude is inversely related to the degree of constriction in the vocal tract - high vowels, other things being equal, have low formant amplitudes. Formant amplitude is also inversely related to formant bandwidth - other things being equal, higher numbered formants with wider bandwidth have lower amplitudes. Formant spacing also affect formant amplitude - if a higher numbered formant is closer to the lower numbered formant, the former is likely to have greater amplitude. As a group, the vowel sounds have the longest duration at about 100 ms in running speech although some individual vowel sounds may be shorter than some individual consonant sounds. Among consonants, the sonorants as a group are slightly longer than obstruents although, again, some individual obstruents may be longer than some individual sonorants.