Well, I haven't tried neither Monolith nor Beyerdynamic models you mention (let alone modded Monolith) BUT a few point to consider here:
1) DT770 is a studio monitor, i.e., would aim for flat response so probably won't be fun for metal, as well.
2) DT770 is a lower tier headphone (relatively cheap studio monitor) whereas M1060 is Audiophile grade (I think) so you'd essentially be downgrading... and probably won't going to like it... at least not initially.
3) Planar drivers are known to respond very well to EQ and are also famous for their "planar bass" so have you tried to adjust the frequency response of your source a bit - raise some frequency bands that your style of metal favors? You know that this is what Audeze basically does with its portable/in-ear planars - applies heavy EQ through a DSP located in the iPhone cable or the Bluetooh module used to connect the earpieces.