I think I've figured out that with the -10dB pad, the C 460 B hits the -10dB minimum mic input clipping level exactly (at -10dB). So, theoretically, I think there is still possibility of clipping when running the pad, and a much higher chance without the pad. Note that this would only be if the sound in the room hit 134dB! But at 124dB, I think I've got some good headroom with the pad on.
I'll probably also set the limiter threshold to prevent the possibility of any input clipping because I like to run my levels hot.
So, I'm trying to decide what I want to do. I'd like to be able to use some more of the gain on the preamp, so I've considered getting a Denecke PS-2 to power the mics and then run line-in to the Mix Pre-D. I'll probably try it with the pad and see how manageable my levels are.
Also, I tested the Mix Pre-D and have confirmed that it does not output phantom power when on the "line" in setting. I'm using the 460s with selectable 12V on the MixPre-D.