For a 4X3X2 oven you'll only need one element. A single 3500 watt broiler element would work fine. Your oven would only draw 14.5 amps.
I can make you a control box to safely control your heating element. It would look like the unit in the attached sketch. All parts would be brand new, with every component being servicable if anything ever needed replacing. You simply set the temperature you want on the digital controller by pressing the up or down button and the control box does all the rest. The temperature is displayed in red led letters on the controller.
If you are interested in a unit like this or have any questions, drop me an email at
kcenicola@aol.com. Good luck with your oven!
Ken Cenicola
NHA Supply, LLC