Am I correct in reading that at this time 3dprinter os does not offer dual head support?
Great question. We actually do support dual head printers however, we will not slice for dual extrusion. Simply upload the gcode from your local slicer to 3DPrinterOS, select your printer type, and select print. As long as the file was sliced properly for your printer type, you should have no problems streaming any dual extrusion gcode.
but your interface for controls does not allow control of the second extruder from what I can tell. I am running a raspberry pi 2 with a 7" screen on my creatr so I have full indolence from a pc so it is important for me to be able to control them separately for feeding and such