Got my first Radeon Pro Duo in today. After a bit of fiddling, my current sweet spot is at 1050mhz core. It ran up to 1120mhz before crashing, but undervolting wasn't as stable. With -100mv undervolt and 1050mhz core, am quite satisfied with the results.
With claymore v4.1 (ethi 8, dcri 60) I am getting:
ETH - Total Speed: 62.117 Mh/s
ETH: GPU0 30.909 Mh/s, GPU1 31.208 Mh/s
DCR - Total Speed: 1863.518 Mh/s
DCR: GPU0 927.275 Mh/s, GPU1 936.243 Mh/s