Once you have selected the beans and procured a batch, it's now time to process it into delicious chocolate. When the beans arrive in your factory, they are scanned for a quick look to spot any defections. If your supplier is someone who caters to craft chocolate makers, chances are the process of sorting is already done. A quick look of the beans and you're good to go to start roasting.
How does one know the roast profile? Simple, run 2 or 3 batches in small quantity in a smaller roaster and taste the beans. Whichever one you seem to prefer is the one you should stick to. Indian cacao tends to be slightly acidic, with bold fruity and floral notes. Hence, to ensure that most volatiles (acetic acid) is removed, I roast at 120C-125C for 35-45 mins. One other profile that many chocolate makers prefer (depending on the cacao) is to crank up the heat and roast for a shorter amount of time. This will really bring out the more "chocolatey" or "coffee" sort of notes in chocolate.
We have a simple open drum roaster that is used to roast cashews and coffee in Kerala. Its economical but this is what we have presently given the size of our business. Several makers opt for a specialised coffee roaster where they have better control over temperature, heat distribution and airflow.
No roast profile is better than the other. It's just what you as a chocolate maker want to showcase/highlight the characteristics of the cacao. For an aspiring chocolate maker, I would highly recommend to visit https://chocolatealchemy.com/ to learn more.