Seat position is the number one most important thing in terms of chassis handling and dynamics. Most major manufacturers have a seating chart to give measurements based on your height. These measurements are designed not only to give you optimum weight distribution but also accommodate varying size drivers.
First and foremost, you set the seat where the manufacturer tells you. This is your priority to get the kart to handle. However, since everyone is different sized, you might need to move it slightly to get comfortable. My thought is always set it where it’s supposed to be and if it’s slightly off but still driveable, the driver has to live with it. If it’s way off and makes the kart undriveable (your legs hit the wheel or your arms don’t reach or something) then you obviously need to adjust it to make sure you can drive.
Unfortunately I don’t have a seating chart for the CRG. Here is the Tony Kart one:
As you can see, it only goes up to 190cm (about 6’1″). Any taller and you might want to consider an extended front porch setup for your kart to get your legs stretched out a bit more.