That roast looks pretty good. It looks to me like its quite light, hard to tell with the lighting, but it would definately be drinkable. Let it rest for 2-3 days then should make a good cup.
It can get a bit nerve racking wanting to stop the roast, thinking that it will go too far. Also ive found the more beans you use, the more time it takes to do everything so using more beans can help learn how to use the roaster as everything happens more gradually rather than all at once.
Ive got same roaster (same grinder and bdb also!) i constantly use 1lb, P2, C. I roast between 300-400g The only difference between 300-400g is the time it takes. I also use P1 if im roasting upwards of 500g to really push the heat into the mix.
With 300g or so with this setup i know it takes roughly 10minutes to first crack.
So if you want to try this give it a shot.
Taste is a personal thing, but i find after you've hit first crack anywhere from there till the start of 2nd crack and youll be pretty good for a drinkable roast. I find if you hit cool at start of 2nd crack, the cooling process will finish off the 2nd crack, as its still hot in the oven.
Also many people do cooling in different ways, how do you do yours ?
I open the door and flush all the heat out and let it run the full cooling cycle, with the trey removed.
btw nice Subi!