Hi Bob, thanks for the photos. I will post my install of the MTH soon.
A quick way to measure amperage draw is to use the RCS charge jack to measure amperage. Take another battery attach a cable with the 2.5mm plug. You will place the battery in series with the meter positive probe. Connect the plus side of the battery to your digital meter red probe, then use the meter black probe to connect to the positive wire of the 2.5mm plug going into the charge jack. If it is wired the RCS way, this battery will drive the loco while you are measuring the current draw. Cool. If not wired this way, then you need to break the connection at the inside battery plus terminal going to the on/off switch.
Hope this helps.
Don