Question Suggestions on how to balance my Rig

It was pretty clear when replacing a burnt wormdrive motor one one side of my rig that it is not balanced well left to right and front to back. It definitely is much heavier on the left side which is the motor which burnt out (black coils, melted plastic inside.. the works). After repairing the sim and solving some wiring issues the left motor is getting hot after 1-2 laps on assetto corsa while the right motor is nice and cool. After searching the forums it is evident that balance is very important for wiper motors and this imbalance to the left could be overloading the left motor.

The frame is steel box tube that was built by someone else. I suspect the additional steel on the left side to hold the control box and wheel mount has added to the imbalance to the left. The shifter and aluminium plate it is bolted too would also contribute a bit.

The seat, and pedals are basically centre however the Uni join is just offcentre to the right by 5mm. Unfortunately this is not easily moved 5mm left as the new hole I would drill would essential join to the existing one!

Any suggestions on the best way to balance this particular design while still taking into account functionality and not redesigning the whole thing?

Attached below are SimCalc screenshots, photos of the rig and a video of it in motion.

One thing you can try is to use a bathroom type weighing scale.
Prop up 3 of the legs evenly to the height of the scale. Place the scale under the 4th leg and record the weight displayed with you sitting in the rig. Move the scale around to all 4 corners and record the weights.
There is a mathematical calculation you can make to show exactly where the CG is presently.
I have used this in the model airplane hobby to find the CG balance point with great success.
I do not remember the formula used right now but in your instance it probably not important.

Thanks for the replies guys. I can determine the centre of gravity however I am seeking ideas on how to move this so the balance is better and more central.

The steel box tube frame is definitely heavy, it was suggested that I could drill reasonable sized holes in the heavier side which would reduce the weight and move the CoG back towards the middle.

Given that the current CoG also causes the sim to want to tilt forward, would making the whole front end lighter also benefit the longevity of the motors as they would have less weight on them and also make them more responsive (less force require to pitch and roll?)

A keyboard and mouse stand is also an idea I had that would shift the CoG from left to right but this also adds weight to the total sim so I need to be careful.

Another way is to measure the currents in your motors. If they are fighting to hold position, current draw will go up. I rigged up custom ammeters on mine to always know balance but there are lots of ammeters out there that should be doable. I started with just a couple of ammeters from an auto parts store but you want to be mindful of voltage drop if you go this route. That’s why I went with a simple custom circuit that uses a low resistance shunt and an amplifier to drive LED voltmeters from the voltage developed across the shunts.

With full-time, real time measurement it’s easy to adjust my chair forward and back to balance if need be for different riders. Your side to side balance should show up too since it’s causing current draw. Details in the build link if it interests you. You don’t need to go all out like I did but ammeters are a possibly easy way to “weigh” and balance your rig. With your motors at the front, ammeters would be near your feet and easy to see. That’s another reason I went the route I did - motors were at the back and didn’t want to route big motor wires any longer than they needed to. Nice rig!