From some recent roasts in my mini drum equipped with a bean probe,
temperatures in degrees C:
Fast ramp approaching first, 6 to 7 C per minute, delays onset of first and
extends duration into higher temperatures, begin 205 C end 210 to 215.
"Normal" ramp 5 C per minute, begin 202 to 203, end 205 to 208.
Slow 3 to 4 C per minute, begin 199 to 200, end 203 to 205 but very few pops
total, often none at all.
Exceptions: Monsooned Malabar, Java Old Brown (sorry SM does not sell),
normal begins 205, end 210 to 212, fast begins 212, end 220 to 221. Kenyas
and Yirg normal begin 199 to 201, end 203 to 205.
Results can be affected by length of heatup resulting in drier or wetter
beans at onset of first. Aged beans seem to shift the entire first crack
into higher temperatures. Green storage conditions may also affect moisture
and range of first crack. As with anything, YMMV.