I personally tend to disagree with flying an NDB approach like an ILS approach. I believe the NDB approach is design to safely bring one below cloud cover in order for one to sight the runway. If one flies a 3 degrees descent, the chances of obtaining visual will be less plus the fact there is absolutely no guarantee the 3 degrees takes one to the threshold!!
In a 'semi-precision' approach such as VOR/DME, then it would be a different story...
HS