There is a huge difference between regular / standard belly dancing and gothic bellydance. Gothic style is not only darknes and sadness, it is also powersurge, feeling of immortality and being out of mortal world while dancing. Sofia Metal Queen says that it is a joy to be a dancer, model and fashion designer at the same time. It is unusual experience to feel the power. Contrasts makes life more colorful.
Best music for gothic metal dances is black metal... Or traditional gypsy bells and/or tambourine can be also enough. Music, in this case, is just support for dance.