I have a slightly different rotation then the HT based ones that most people use for 40 dura. It has a lower chance of 100% HQ, but its more consistent in results. I get a minimum of 58% on the quality meter, but usually hit somewhere between 84-88%, sometimes even 100 depending on condition states.
out of hundreds of 40 dura two star synths (this is pre patch), I'd say I get an HQ 4 out of 5 times, which if your going for all 8 master books, 40 out of 48 ain't so bad. The hasty touch rotation in the thread adoxx posted is also very good, I just have really bad luck with hasty touch.

Here's the rotation (note this takes a butt ton of CP since I'm not using hasty touch)

40 Durability Rotation 4 (No RNG, ~75% HQ Rate)
Comfort Zone
Inner Quiet
Steady Hands II
Basic Touch x2
Manipulation
Basic Touch
Great Strides
Steady Hands I
Innovation
Advanced Touch
Great Strides
Bygerot’s Blessing
Ingenuity II
Careful Synthesis II x2