On a 3 degree glideslope rate of descent is groundspeed x 5.
100 knots groundspeed is 500ft per min.
Go fly around in practice area and find the power setting which gives you that rate of descent in that plane in the configuration you want to fly the ILS.
Set power setting at that level, intercept glideslope, if you need to then modify power to find rate of descent which will keep you on glideslope when miles out and needle not sensitive. Leave power there unless you have no choice.
Trim it up, use trim to maintain glideslope. Small adjustments, trim, trim, trim.
Don't f**k with anything until you have crossed the threshold, runways with ILS on the end of them are long and you won't run off the end (usually!)
This thread has confused the hell out of me!