I agree with Dick. and more importantly - whatever works for you personally.

When I was very young, I had a thick almost impenetrable Lancashire accent - learned from my parents, I was Lincolnshire born and brought up. When i started my A level English course, i was horrified to find out that i was excluded by my accent from western culture - declaiming TS Eliot's poetry simply didn't work with a Lancashire accent.

let's go then, hugh and Ah
Wen't moon is spred oot cross t't sky

Is it coincidence that all these smart arses who say sing in your own voice have nearly all got nice middle class voices and sing like Long John Siver/Walter Gabriel? i mean , lets face it, it is all bollocks isn't it? You have to make an effort to engage with the song or the poem. do what seems right to you. if people are unsympathetic to your efforts - well that's their loss, and their snobbery that's stopped them from engaging with you as an artist.