Live is fine. Do what you're used to.
I suggested different load only to speed up the process by increasing the amount of current drawn from the DAC. But that is a presumption on my part, that working the DAC harder speeds break in. That's just how I do it.
I skimmed the Zodiac manual - Zodiac XLR outputs have professional voltage level so they can probably handle a 600 ohm load, but the RCA outputs are consumer voltage level so the lowest input impedance you should connect the DAC to is 5kOhms, imo. Every commercial consumer product will have input impedance of >10k. The only inputs lower than that I've ever heard of were some older Oddysey amps which were 7kOhm input. New Oddysey amps are higher now iirc.
Lower load impedance will draw more current from the Zodiac output stage amplifier, which, along with signal conductors and caps after the amp stage, are the actual parts you are trying to break in. The digital circuits ahead of the output stage will also break in, but that is a fixed rate that you cannot change with load variation. Some people think any music signal will achieve break-in, while others think higher current speeds it up, while others think break-in is a delusion. ymmv
As for the volume level, turning up the Zodiac volume control also causes more current output from the DAC, as long as it doesn't cause the DAC or the input to clip. I doubt that the DAC would clip, but it is possible to clip a consumer input stage with professional level voltage. So it's a good idea to listen to the break in setup for a moment to make sure it's not clipping before letting it simmer for hours. If your DAC is connected directly to the amp, it would be too loud to listen with the Zodiac turned all the way up, so nevermind about maxing the volume control. Just set it to loud but not clipping level with a modern pop music track, then switch to frybaby and shut off the amp. Remember 2/3 of opinions say volume level doesn't matter, so feel free to ignore this, or better yet follow your intuition.
The phono preamp inputs will most likely have 47kOhms (for MM) and 100 Ohm (for MC) input impedance, as these are the most standard settings for carts. 100 Ohms is too low for the DAC. 47k is safe, but not much different from the DNA in terms of current draw in the DAC. Your DNA 1.0 amp's input impedance is 100kOhms. Long ago 47k was the industry standard for RCA input (they used to call RCA a "phono plug") but now many RCA inputs use the 10k standard. 47k and 100k are both on the high side, which is good for normal use because it makes easy work for wimpy sources like old fashioned (good sounding) simple circuit tube preamps, but not hard enough for strong workout needed for fast break in, imo.
As you say, it already sounds good enough to listen, so speeding it up doesn't matter anymore. Just listen and enjoy. Be aware that SQ might dip down again as break in continues. Just ignore it. Listen to the music, ignore the sound.