Make sure your latch is in the correct position, put the seat on, line up the front and push from the rear until it moves into the holes. Then place on the rear by lining up the back of the rear seat first.
It did fix the abrupt throttle. I am running the config exactly like you listed. I did, last night, try the 419-001 but it's too early to determine mileage. I'll post back after a few hundred miles and let you know what I find. I am running my bike stock.
Bought the Kuryakyn Universal Throttle Boss for about 10 bucks and it is one of the best cramp busters I have found. Smaller in footprint and not in the way as much as some I've had. Great addition for little money. Here's an example...
Great trip report. I've traveled alone for years and actually have a hard time riding with others now. It gets in your blood and it is a disease you can only cure one way......Road Trip.