For what it's worth I use two different methods. I always want to be 250kts at 5000' with 20nm to run. Outside this distance I want to be intercepting 4times my altitude. As an example at 60nm 15000ft is my reference. Normally I am a little higher than this but as long as I'm intercepting the 4x (eg 10000 at 40) I feel comfortable.
If I feel I need a more accurate picture (chance of getting cut in by ATC) I use distance x 3 - 4000 if at 300ish knots, -2000 if at 250 and a straight 3x if at greendot.
For an ILS (IAE 2500) take flap 2 no later than 2000. If heavy or tailwind allow more (2200 - 2500). Once flap 2 continue configuring - don't delay as you may not have above idle at 1000/500 for stable approach.