"Build to the mod" is just a way to say that I've never heard as we always do that.. but it's building to the battery to me. ..
Thinking about this more, I don't think I explained the term properly.
I have run a 0.03Ω build on the Hohm Wrecker just for the novelty factor of it. Hohm Tech "claims" that the mod will fire down to 0.01Ω, but I cannot get it to do that. That measurement must have been done on a test bench, for proof of concept, with a different firmware that what was released to the public.
I ran this 0.03Ω build with a pair of their Hohm Work 20A batteries, they drained fast and got warm but not hot. I wouldn't have even considered firing that build on a mech mod with 30A batteries, let alone the 20A Hohm Tech ones. It would have been disastrous, so the term building for the battery really only applies to non regulated devices for me.
When building for the DNA75 single cell mod, I keep my builds in the 50W range, but still try to keep a heatflux of ~250. It would be nice to put a chunkier build in it that requires 70W but there would be no battery life at all. To me that is building for the mod.
On a multi battery mod like the DNA166 or higher, I build for the atty using chamber size/airflow as the primary factors. Instead of what kind of power is required to hit the 250 heatflux, since I have excess power to call upon.
On my iPWM box, I have to build for the batteries since it fires through a mosfet at the current battery voltage.
Does this make sense?