mine at viabtc.com
you can give them two addresses
ltc and doge.
I did try to hook up my L3+s to viabtc but I can't calculate profit, only way I see is to set like 12hrs and see what's up.
So I just plugged them to nicehash, which I'm not very proud of.
this not belongs here but I'm pretty sure I can get more hashrate than 510MH/s the stock firmware offers, most legit one I've seen the firmware was awesomeminer's one, if any recommendations I'd love to hear