Hi, this is my first contribution to Thingiverse. I was inspired by the Netfabb calibration system. Although not so sophisticated as theirs my system can help you dial in your flowrate settings.It should be quite straight forward. Have a look at the formulas. Enter required data on the first (Summary) page (Yellow fields= Feel free to change; red fields= Dont change so often :) ; Green Fields just for reference; The rest= Don't touch...)You can use http://www.thingiverse.com/thing:5310 for the startup values and then refine..Then Copy "Column A" of G-Code sheet. Paste into a text editor. Make necessary changes, Change extension to Gcode. Enjoy...