ANSWER:

Yes, this is authentic and it’s best to count on your right hand fingers as they would bear witness for you on the day of judgment. 

https://youtu.be/u9DWUZvRYl0

Saying Subhan’Allah wabhamdihi 100 x is authentic and can use a counter to count until 100

Supplications | December 29, 2018 7:04 pm
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Sheikh, there is a hadith that says a particular dhikr is equal to approx 6 hours of dhikr that our prophet (saw) taught to his wife. It goes like ” subhaan Allahi……wa midada kalimatihi.” Is it authentic and how many times do have to say it?
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I have been reciting my adkhar for a year but I have been reciting them in english. When I recite in Arabic, I can’t focus on the meaning and have khushoo.