I got a 2nd XFX RX 560 (2GB) running on my Onda D1800 and here's the relevant portion from the .conf file for SGMiner-GM 5.5.5 that gives me the best performance (so far, anyway):
"profiles":
[
{
"name": "xmr",
"algorithm": "cryptonight",
"rawintensity": "416,416",
"worksize": "8,8",
"gpu-threads": "2,2"
}
],
Again, this is for two GPUs; if you have just one then there should only be one each of 416, 8 and 2 in the above profile. Conversely, if you have more than two then extend the comma-delimited list as necessary.
Getting a very consistent 460 H/s per GPU with 1200 core / 1900 mem and 100% power in MSI AB. Also used the one-click timing patch in PBE and patched driver with pixel clock patcher - the usual shenanigans required with AMD cards, in other words.