Haven't dual mined in about 2 years. Basically every dual-mineable coin ended up being mined by FGPA or ASICs shortly after. The reason why is because for a coin to be dual-mineable it doesn't need memory, basically just compute operatations like BTC's SHA256. Hence its crazy easy to design an ASIC for any dual-mineable coins. However the fabrication cost might not be worth it.

So for the medium cap coins like DCR, they made some ASICs and for others they made FGPA and it was game over for GPU miners. You can go to whattomine and there is an option to calculate profitability based on dual mining but by the looks of it, doesn't seem profitable at all.