easiest way to move pedals

Looking for easiest way to move thE pedals back. Last driver was around 14 and my son is 5. I would love to keep existing pedals useable in case something is acting up I can take it out. Tried a bar bolted from current pedals to a new set couldnt make it work. It kept binding up. Any ideas.
Get a extra set of pedals and a set of pedal risers. Mount the pedals baxkwards in the risers and make linkages to attach existing pedals to the new pedals.
keep existing linkage on existing pedals. mount new linkage from new pedals to existing pedals. use a riser like xxx40 suggest. turn pedals backwards so linkage mounts face forward on pedals your son will use. or buy some ultramax pedals and rerun brake and throttle lines.
pedal blocks and some 5/16 rod. mount the blocks, get a measurement and bend the rod. drill the pedal end with the 90* bend on it for cotter pin and thread the other end with 1/4 x 20 tap and there ya go.
We had one guy that made pedal extensions with a 4" wide piece of PVC. set on oldest boy kart made with 2" dia. PVC and Youngest son's kart with 3" or 4" PVC.
He cut two slots for hose clamps slipped the 4" wide PVC over the pedal and tightened the hose clamps (2 each) onto the pedal. Put a couple decals on and they looked great.
The drivers foot pushes on the round part of the PVC.
Has anyone used the ones from fastech? How does it mount to the kart? Does it bolt through the floor pan? They look like a great design, the traditional type we use now the floor pan flexes a lot.