Hi Berlopez.

Firstly. I'm using the 727 v2.3 without any mods.

I have found that the trick to catch the ILS and GS is to come into it at about 10 degrees or less than the Localizer heading and below the Glide Slope.

I use HDG SEL and ALT HOLD and I have the Mode Selector Knob on AUTO G/S as I'm coming in.
My altitude is at about 3800' AGL at around 11nm from the airport.
When I get close to the Localizer the HDG SEL disengages on its own accord and starts turning onto it.
Then as the Glide Slope is just about at the centre of the ADI. I manually disengage the ALT HOLD. This allows the plane to follow the Localizer and GS to the runway.
As it gets close to the Runway Threshold I have to turn the Autopilot off or it will start climbing again just prior to landing (it's as if the GS starts to go up again at that point).

Hope this helps.

Mark