Any slokam is as good as any other.
I think it is all in our mindset.
I wish you would continue the the family tradition
by using another version or another rendition.
You may play the Youtube presentation - if you don't have the words and tune!
God/ Goddess want ONLY our ciththam (mind and thought ) and nothing more or nothing less.
Krishna is called as Chith ChOr since He steals our chiththam
which is picturised as the fresh butter He is extremely fond of.
When my dear mother passed away a few years back people were amazed to see the tejas and brilliance in her face even after her demise.
The purohith who had come to perform her last rites told us her children,
"If you want anything in the future you don't have to pray to God. Just pray to your mother. She will give it to you - whatever you wish for!"
I say the same thing to you. Since you have so much regard for your grandmother, pray to her first before you perform the Navarathri puja and she will make sure that it is accepted by your Goddess.
Happy Dasara (in advance) to you and your dear ones!
AND No shedding tears on auspicious days and occasions!!!