If you want what may better be referred to as a, 'dialect', (Dialekt in your case..), then simply learn from the appropriate community.
I learned Deutsch from a born Wiener! Ha ha, but I prefer to speak properly most times - and so does he.

Almost every "A" is pronounced as an "O" in the Viennese dialect. Unless it has changed considerably since 1974.. But then Karl Moik certainly shows it well.. "Wenn ich mit meinem Dackel..".