Hi,
The develope times depent on contrast you want, shorter times for low kontrast (when using hard light condensor enlarger) or high contrast for diffuse light source. Also the film size is important, becouse 135, 120 and sheet film does use different of different thinkness- therfore also different times. D76 is not really fine grain when used pur. Use D76 1:1 or better 1:3 mixed with water- You will get finer grain, better light and shadows, much better gradiation in all. The times will be in that case about 15 min (1:1) or 20 min (1:3). At longer times and softer developer you dont need to be so exactly as with pure one. Never go above 20 Celcius. I prefer X-tol for Tmax (Tetenal Negafin should be the same when I remember-I did not develope fim since some years)
all best
roman