Well there are 2 ways to control an oven with PID:
1 is by modeling an oven and hope that it will follow the curve. If you supply the oven too its ok.
2 is too make a learning routine in controller, or give customers the ability to adjust PID gains to get a decent result.
The trap for young players is that ovens are not linear 2nd order systems, they got an "s" curve at beginning which may cause fast rise up since PID's error goes bigger n bigger and at the end its so hard to remove the heat.
My idea was to add many points, each point can have different gain set so you can achieve a nice ramp with high gains and before reaching the limit lower the gains to remove overshoot. So you make a few trials, you build the profile for you hardware and then you are good to go.
If it doesn't follow the line you tweak P, I, D on problematic point and its fixed without destroying other phases.
Not easy for newbies but for engineers its absolute freedom. So hardware doesn't matter as long as it can heat up quickly.
Yea I am gonna make it a complete set (hacked oven, no time to build my own). It may look nice n dandy in custom pcb but its just a atmega2560 with FTDI, micro SD, buck converter, a 3.5" nextion display and 2 max31856 thermocouple readers. Software on Arduino so everyone will be able to make it with modules from ebay. But that's another topic, when its completely bug free and got a perfect curve I will make a topic. I hope in next month.