Just look for OEM replacement heater elements and oven fans on eBay. They are very cheap and very simple, so no need to try to shoehorn anything from another application that may not be suited to being in an oven.

If I can understand properly on eBay, all those heating elements are replacements for some kitchen oven models. That's the same thing as I was thinking to buy here. Find some reputable store that sell replacement parts for ovens and buy it. If that's correct I will avoid postage cost and waiting part. 

What is in the box with Omega CN7800? It would be of great help if you can tell me what SSR and what thermocouple to get since I really have 0 experience with those elements.