Good on you, welding is a very useable & useful skill to have
So, can we see your kart?
I am still deciding on the seat. Make one of my own design or buy one because it definitely needs one. Not sure I understand the last question?
It looks like you have the accelerator clipped onto the steering wheel. How do you turn the wheel and still work the lever
That is commonly done, Paul- with direct steering, there's generally only about 90* of steering wheel rotation from lock-to-lock. Very manageable with a hand throttle on the wheel. I have the same setup on my race tractor...