According to Wikipedia, jizz is 2-5% sperm by volume. Assuming the mean of 3.5, that’s still a 3.2cm sphere of sperm; add all the supportive tissue and germ cells surrounding it (which make up the majority of testicular volume) and that would definitely be larger than the typical 5×2×3cm ellipsoid.

Each individual ball would actually be about 9.85cm, assuming they’re both the same size.

https://www.wolframalpha.com/input?i=diameter+of+a+0.5L+sphere+in+centimeters