The risk of war with China is not that great. China can't afford to lose their exports to the US, and the US can't afford to see what would happen if China flooded the market with their massive reserve of US dollars.

I would guarantee that the per soldier spending China commits is much, much lower than what it costs the US. A Chinese solider is a guy with a gun, a US solider carries thousands of dollars of kit and is the product of millions of dollars of training.

In the context of percentage of GDP per person then China is probably much higher.

Percentage of GDP suffices. Otherwise you will be multiplying and dividing by population.