You want to calibrate your extruder before you continue. See the Sailfish guide, particularly Chapter 5.

Feedrate is the term your looking for. Print speed is a colloquialism.

Slicers cannot be used to give co-ordinate specific move commands, they can only read whichever stl file is loaded and 'slice' that. If you want to do a custom path you would be better off writing gcode directly, opening it in RepG and exporting a x3g.