Background
I have spent a fair amount of time thinking about the best pedagogical practices for teaching pants fitting and my approach in particular which is body-neutral and uses commercial patterns.
There is a lot of information to assimilate for people who are new to the slow fashion world, but also a lot for people who have experience making garments and fitting them with traditional approaches. The former needs to master basic know how such how to handle a machine plus a new technical vocabulary. However the latter has perhaps the more challenging task of letting go, or unlearning traditional assumptions associated with pants fitting in addition to learning how to make decisions within a new framework.
At the outset, I had a sense it was going to be tough to get experienced sewists to try my approach. Pants were considered to be the most difficult garments to fit. Standard wisdom was that you only needed to fit pants once and then could use the same crotch curve for all styles. And so, even though the traditional fitting process was arduous, once you struggled to the end of it at least you would never have to repeat it. Convincing people it was possible to have a streamlined process that is not only simpler but reliable, delivering results just as good or even superior to conventional methods was going to be a challenge because it was so contrary to accepted wisdom.
So I mostly focused on helping makers how to be successful with the approach with a quality basic pattern (check Threadloop for a suggested list). This is also why I highly recommend starting with a pattern that has a straight waistband. It is easier and quicker to cut and construct, uses less fabric, easier to keep stable, easier to adjust and easier to handle during fitting. All this helps the maker to focus on learning the approach. Like everything in life, there is a learning curve and body neutral fitting with TDCO is no exception.
If you are not starting off using a straight waistband, the next best thing is a pant with a waistline facing such as 1010T (Christine Jonson Trouser leg pants for wovens).
However, not everyone or every pattern wants a straight waistband or a facing. And most contemporary pants styles sit lower on the torso where a contoured waistband is a great option. This is how I prepare a contoured waistband for TDCO fitting.