Hi Chris.
I used a 50W TEC (Jaycar) which drew around 4.8A max. I used a separate power supply to the system so as to not induce noise onto my other 12V equipment.
4C stable is excellent result. Try to keep the camera nose pieces and Drawtube (DT) connection well insulated as well. The OTA and focuser (and ambient) will be sinking a lot of thermal efficiency from this area.
I just wrapped insulation material (like stubbie cooler material) around this area.......crude but worked.
As you have found...cooling really reduces sensor noise. Congrats!
