Phonemic chart | Teaching English | British Council | BBC . The same site must have diagrams of mouth positions.
As to your second paragraph, I'm surprised. One would expect the [b] to close the /æ/ vowel more than the [d]. (You can hear this quite clearly if you can stand to watch Mary Poppins - when Julie Andrews sings 'Feed the birds, tuppence a bEg' -in which she's advertising the cost of bird food: '2d [that is, less than 1p] a bag')