I need to close out this thread on a very positive note. Problem Solved!! 
...with a shout out to John Meyncke who emailed photos of his modified culvert beam/track showing the new switch position. THANKS JOHN!!!
John graciously agreed to have me attach his photos to this thread so others who might experience this culvert drop issue will have the information to make the change. The two holes (I used a #47 drill bit) were moved outward on the beam by 0.40"....based on John's photo with the taped scale attached. And that resulted in a MUCH better drop of the culvert into the car!...
As John pointed out...look closely at the first photo...Lionel apparently made two sets of holes in determining the best micro switch position. The screw heads show the second...successful...holes to be about 0.4" from the original set.
The last photo shows a further modification John made to his loader. He removed the man holding the trolley control tether, and replaced it with a railing/platform of sytrene construction, painted a matching red. Well done, John!!
I also want to give a shout out to Sean... He was spot on with the rough edges/inner surface of the metal culverts. Cleaning them up with a jewelers file and emery paper made them smooth as a baby's butt, and I've no doubt it aids in the smoothness of the release. Thanks Sean!!
This experience reminds me why this forum is so valuable!!
Time to celebrate!
KD
