Not having used a loose TC and only [s]experienced[/s] just a beginner with my digi probe I have no trouble maintaining the 15-30 odd degrees/min to first crack and then backing the HG off to the 2 to 4 degrees / min to SC.
My Bosch HG ([s]LED[/s](<--Oops) LCD model up to 650C) generally sits on the second airspeed setting with a starting temp of 350C at about 150mm above the beans and I touch it up or down based on the per second intervals Im seeing on the probe. *If its rising at 0.3 or 0.4 per second degree intervals then I leave it alone. *If it drops to 0.2 or stabilises Im usually bumping it up 10 to 20 on the HG (no height adjustments).
All very non-scientific of course but geez I enjoy the 20 odd minutes of my roasts and the probe does make the job easy (Havent tried to pull out the beans before removing the probe yet - phew). *My Sunday Roasts now consist of a Lamb & Veg combo with 2 x 500g green bean lots * ;D