Just roasted a 200g charge of Yemen Mokha Ismaili from Sweet Marias. This bean has a subtle first and second crack (burned the hell out the first batch I roasted a few weeks ago because I was not paying close enough attention). This was from a pre-heated roaster (chamber temp around 300F) and roasted a little ways into 2nd crack. Before first crack, I ran the roaster at full power. After 1st crack I backed the setpoint down to 510F resulting in about 80 to 85% power. I calculated rate of rise for the (approximately) linear portion of the bean temp curve before 1st crack (16.9F/min) and after 1st crack (8.3F/min) plots are below.
Going to have to wait a few days to sample this — I think SM recommends at least 3-4 days of rest for this one.
Some cursory research yields this information on development ratio (time from start of first crack to end of roast divided by total roast time). Also found some information suggesting that ROR < 5 or 6 F/min is problematic.