When my steering feels heavy it means the back end is stuck. More caster frees up the rear. Yes, less caster will make it steer easier but you also want it to turn. Going to the top holes will give you more leverage and you’ll have to crank the wheel more for the same jacking effect.
FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience