Hi,

According to me dummy school isn't the best option because in coaching institutes like Aakash, the main emphasis is on competitive examinations and not on board examinations due to which your board exam result also suffers. Since, the main emphasis isn't on board examinations and you don't have much practice when it comes for subjective papers as even though the syllabus is almost same yet there is a lot of difference when it comes to attempting both types of examinations, thus I'd suggest you to not to go for dummy school and continue with the regular school along with coaching as it will ensure your familiarity with the subjective exams too.

I hope this helped you. All the best!