On the fork oil I had the same question. I've been using 180cc for clean and dry forks and 150cc for changes. I like the AN tutorials but often come away with "what about" questions.
For future reference:
You need a hammer impact screwdriver, not a powered screwdriver of any type for this. Just an example - lots to choose from:
https://a.co/d/3noMx2i
Mine is at least 40 years old and I lost the bit set to I bought this set:
https://a.co/d/7qWac8M
It/they have never failed - oil pump screws, sprocket screw, fork drain screws, Norton tach drive screws, Triumph "trap door" screws, and others.
IMHO, you're lucky the powered screwdriver didn't make things worse by destroying the slot or breaking the head off the screw.