I don't have MScaler and prefer the Empy in high gain because to me it sounds a little bit more dynamic and alive that way. I didn't burn in the Empy, I was using it from day one. Perhaps it opened up a little bit in the first 150h, but I think most of the burn in happens in the brain. I would say -22H/-24H is a comfortable listening volume. If I want to party it goes up to -18H sometimes, for quiet times -26H is enough. -10 is painfully loud, I think that must be because you have the MSC in the chain. Or you are in low gain. I have just checked and -10 seems pretty loud even in LG. -10 in LG must be somewhere around -16 in HG. I don't think volume matters too much when it comes to burn in. As long as the transducers are moving it is fine.