Yes you can is pretty similar but you can't go as heavy as you would with proper farmer handles. If at some point it gets easier with heavier DBs you have, then try and use just 1 DB instead of 2. This will make it more challenging on the core.
I am training for a contest and one of the events is Squat for Reps on 205kg in 60sec. I am hoping to get 8 reps in total and that's why I'm doing sets of 8.
depends on what your specific goals are (i.e. how you prioritise strength, muscle mass, endurance) and time under tension (i.e. what magic feature of 12+ reps necessarily makes them better than less reps with a super slow eccentric phase?). there's also variation with body types and even just plain personal preference, and what would be wrong with that? there is not just "one way" to approach lifting, or exercise in general. the one constant with lifting to make physical gains is contracting your muscles under tension until you "max out" or very close, triggering adaptation.