My Mid 2010 MBP 15” definitely has T6 Torx screws for the HD. I replaced my 500GB 7400RPM Seagate with a Samsung EVO 860 500GB SSD. I now have a new machine! Can’t believe how much difference this made! Also used Carbon Copy to clone my old drive to the new SSD, worked perfectly.
I used these instructions to upgrade my mid 2010 15” MBP. Absolutely spot on! Thanks for taking the mystery out of how to make this upgrade. BTW, I installed a Samsung EVO 860 500GB SSD, no cable issue (thank goodness:-).