When you see the front tires balloon that is the center diff unloading. This can also happen side to side with the front or rear diff. The diff fluid resists unloading whether the tires are in contact with the ground or not. Finding the right balance to prevent excessive unloading while still allowing the outputs to spin at different speeds is the goal. Believe it or not increasing the weight of the fluid in the rear doesn't always promote oversteer, in fact a heavy fluid or locked rear diff can promote on power under steer. I'd start with the 7/10/3 as well.

Edit: In case it wasn't clear, making the fluid heavier in the center diff will transfer power more equally between the front and rear tires resulting in less ballooning of the front tires. Right now the front tires lose traction during weight transfer, power unloads to the front tires which are spinning instead of accelerating the truggy. Increase the weight of fluid in the center diff and more power will go to the rear which has traction increasing acceleration even when the front tires are off the ground. Making the rear diff fluid heavier will transfer power more equally between the rear tires. Try 3k in the rear first and if you're spinning the inside tire during turns then make the fluid heavier, no more than 5k should be needed though.