If the EC oven is big enough then this is the easier, albeit more expensive route. I would probably have done this if it had been a lot bigger.

Building the oven is pretty straightforward. I used 2" thick insulation board sandwiched between surplus timber ply sheets and lined it with silver foil insulation. Heat is generated by 10 150w bulbs, wired in groups and individually switched so there is some control. One of the groups is connected to a simple PID (around £7) which is easily connected. I added several cheap digital thermometers so that I could check that the oven was getting hot evenly and a metal desk fan to help in this regard.

My PID just controls the temp, there is no ramp or dwell options. However, I get around these omissions by switching on the separate circuits as the temp rises, using the one attached to the PID as the regulating circuit. Requires constant supervision during the ramp phases but I can leave it during the soak periods.
Works pretty well with 130 deg C achievable. More bulbs would result in higher temps if required.