With regard to your questions.
The electronics I used is minitronics (for info see reprapworld.com)
The mintronics is supplied with a 12 volt cooling fan for cooling the print. So I made a hole in the bottom and mounted the fan below the print. For a better air supply to the bottom i made higher/longer legs for the cube.
The power supply of the minitonics can be up to 24 volt (if the correct jumper is removed.). If the power supply of the mintornics is 19 volt ( I my case, I had a 19 volt power supply from an old printer) than the power to the hotend is also 19 volt. This is sufficient to heat up the hot end.
The power output of the minitronics for the cooling fans is also 19 volt. So I use a second 12 volt power supply for the existing fans and the one that came with the minitronics. I did not test the exiting fans with 19 volt (fear of burning them).
I did put 2 thermocouples on the extruder stepper motor during a 2 hour print. After one hour the surface temperature of this stepper is stable at +/- 40 C. The other stepper motors are lower than 40 C (estimated by touching with my fingers).
During my first runs the steppers became quite hot so I reduced the Vref with the 4 pots on the print.
A the moment I am running with Cura 14.09. Layer height 0.2 mm. I did not test any other heights. The prints look very good (better than my home made Alu mendel http://www.thingiverse.com/make:72807
With Cura I start with gcode M84 S0, to prevent the bed falling down. Than home all axis, especially the z axis 3 times. Then I start the print. In the end gcode I removed M84, also to prevent the bed falling down.
I you have any other questions please let me know.