I used one of these for a couple of years before it developed problems. I played with temps and times quite a bit with generally good results. I settled on starting at a higher temp to get closer to the medium yo medium-dark, then backing off the temp to encourage more flavor development. My main problem was not really getting a good temp reading on the beans so consistency was an issue. The bed temp varied widely after a year-and-a-half so I'm upgrading to something better. This isn't a bad way for someone getting started on a budget tho.

I’m going for a dark roast and so I’m going with 25 minutes. I’m at 19 now and it’s smelling really good but not dark enough for me.

It isn't really roasting, more of cooking. The moisture is trapped too much and there's no chaff removal which can cause off flavours to develop. The roasts lasts for far too long. Would be better going at max temp and just stopping after secon crack based on colour. Might even be worth lifting the lid to let moisture escape when the beans start to brown.

interesting, but looked a bit non uniform

the coffee is not ready yet need mora time in the roaster you need to learn littler more before you make a video about roasting expresso coffee...