CG stands for center of gravity. Sorry if this is stuff you already know, but apart from the weight-jacking effect through caster and scrub radius, the kart’s ability to rotate depends on an appropriate center of gravity to be able to lift the inside rear wheel. Oval and road racers/enduros don’t prioritize CG, and so they often use seats that you mentioned in your initial post. Those seats will get you very, very low in the kart. In most sprint applications, that seat will keep the rear flat causing huge amounts of oversteer (bind). Now, if you’re a bean pole, they might work, but otherwise I would go for a more traditional seat. If it’s the greater support that attracts you,look into seats by Deep Seat or Ribtect.