For my fellow gym rats?

I'm finally get back into working my core in the gym after a minor-ish back injury caused me to have to nurse it back to health. I've recently decided to see just how cut up I can get, especially in my core. I've always admired guys that have super defined cores.

For those who are more than casual gym goers and have seen results, do you find that volume > weight is the best policy? Or do you try to challenge your lower back, obliques, and abdomen with heavy enough weight to really get the muscle tension going?
For my fellow gym rats?
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