The Flight Director gave me a lot of grief in my initial Ng time. Sometimes you need to "look thru" the F/D.
Try the following figures as a starting point and fine tune from there.
Prior to G/S slope capture single engine, think 5,6,7,8.
5 degrees flap
6 degrees attitude
78% N1
1/2 dot under slope, gear down, flap 15, maintain 6 degrees (a little forward pressure required)
At G/s capture 2.5/3 degrees attitude and approx 73% N1.
Two engine figures can be extracted from Flight With Unreliable Airspeed tables in QRH.
ie 737/800 24k 60 000 kg
Flap 30 1 degree attitude 58% N1
Flap 40 -.5 degree attitude 64% N1
Use these as a start point and fine tune from there.
Good Luck!