I started with dairy equipment. We had everything welded in for us. Not sure how much help I can give you but I've definitely been there. The used dairy tank we had for a MT had a paddle installed when we got it and just had 2 screens designed for the false bottom.
The BK we used a burner attached through the side and had an an element that ran across the bottom 1/3 of the tank.
We did not used dairy equipment for fermentors, we used plastic conicals heat wrapped in a cold room to control fermentation temps.
I can honestly say that dairy tanks are a good way to get started when you are on a budget but no doubt it is a short term solution. Once you move onto professional equipment your life will be much, much better. and so will your product.