There isn't much point in following step-down altitudes intended for a non-precision approach when flying an ILS. It just adds to workload. You want to capture the glide slope as far out as possible, where the sensitivity is lowest, and make the transition from level flight to glide slope descent once.
So if I crossed an IF at the crossing altitude, and inside the IF I could theoretically descend another thousand feet prior to the FAF before picking up the GS, I've just increased my workload because I'm descending, then leveling off, and descending again at GS capture at or near the FAF, and now it's more challenging because things are happening faster, being closer in. It makes little sense and there is no benefit that I can see.
When you cross the IF at the minimum crossing altitude, you will be 10-15 miles from the runway and well below the GS. Keep it simple; just maintain that altitude to GS capture and then start down. The higher you are, the farther out on the beam you are, and the easier it is.
If ATC is positioning you, which is the case most of the time flying a STAR in a busy terminal area, the controller will either descend you to the IF crossing altitude or some other altitude, possibly lower if the controller's vectoring altitude allows, and you just fly that to LOC and GS capture (note that the vectoring alt the controller may place you at is unpublished - so if you are below a published alt due to an ATC instruction, and you have a comms failure, you are supposed to immediately climb to the applicable published altitude).
So, when flying an arrival in a busy terminal area in an airliner, you will typically fly some of the STAR segments, then at some point close in, the controller will put you on vectors and have you descend to whatever altitude the controller is using for traffic stream using that ILS, eventually placing you on an intercept heading for the localiser, clear you for the approach, and you just maintain that altitude for Localiser capture and Glide Slope capture. The controller will always make sure that you are placed with ample margin below the glideslope path and if they don't, they've messed up.
I can't speak for Heavies, but in the CRJs I flew we would drop gear and go to flaps 20 to 30 (landing flap is 45, selected farther down), and call for part of the landing checklist, at GS capture. The drag from the gear and flap selection would get you started on the descent, along with the speed reduction for the flap setting, pretty much automatically and you didn't have to make large thrust reductions or trim changes. Full landing flap was selected above 1500 ft, usually just before the FAF.
The most important skill for hand flying ILS approaches is use of trim and (gentle) manipulation of thrust. I used to have simulator access outside of scheduled training, and used to spend a lot of time practicing ILS approaches on "raw data", that is, Loc/GS needles only, with the Flight Director turned off. Quite a concentration challenge in a jet going 130kt, but if you got it trimmed hands off on slope and on speed, it wasn't too difficult.