Looking at the Dintree schematic,
It seems to me that the back-to-back 10µF polarized capacitors should be replaced by a single 4.7µF non-polarized capacitor. It’s not like non-polarized capacitors of that size are horribly expensive.
Having two polarized capacitors back to back doesn’t protect them from being reverse polarized, it only ensures that at all times, one of them is reverse polarized, doubling the number of parts susceptible to failure.
EDIT: BTW there is a verified stripboad layout thread you might want to post this to.