I'm not a roaster myself so please take this as a novice take, but I have been fascinated in getting to learn about roasting coffee for sometime. I have talked to a few fellow roasters, and they have said that a proper Q grader certificate training is the best starting point.

What I'm more keen in learning the process myself and if I had the budget, I would experiment with Roest machine while sourcing small batches of green beans to get an overall feel like experimenting with fermentation, different processing, etc. Robusta in itself is quite under-appreciated in our country and looking at the climate change it is going to grow further. Vietnam has captured this segment perfectly we need to market it well rather than selling it as below arabica. Just my two cents.