Is there a section in the "Open Reference Manual" that gives a step by step on how to do this?

On my own, I tried saving the background and got a "KML" file, but just importing it to the map didn't make a difference.Once the maps are generated, I still get one map with the palette I want and the adjoining map with no palette at all. (Raster and with no IMC "By Hand". Don't know how.)

I can try Vector like you suggest, but the detail isn't very good. You have to zoom way in on the map to see all the 1' contours that I need, at least that's what I have to do when I make a user map with the "Export with a Preset Style" using the "AT5 Vector Map" selection. Maybe there's a better one?

Detail should be just as good in vector mode - perhaps try a different palette, if the difference between depth areas isn't so clear? The actual contour lines are the same regardless of whether you export in raster or vector mode - it's just the background that changes.

The way that you would combine images into a single raster map is to export the background raster of each map that you need, into the same directory. You should end up with a bunch of .png and .kml files. Then you run the IMC by hand (start the InsightMapCreator.exe application), and select the Raster Mode processing mode. You need add your image directory, using the Add Folders button and set a suitable output directory (create an empty directory somewhere, and set this as your Work Directory). Then pick a min and max resolution - try 1 and 8 to start with - and click the Build button. This will kick off a raster map generat, the results of which will end up in your work directory.

With out any other changes except for using Vector instead of Raster, which "Preset Style" for Exporting a map do you recommend?

On the Raster versions I've been using it's the AT5 Map with Flat Raster Background and the palette has been the RGB white for deeper water to medium blue for shallow, as in the pic below. I really like this color, a lot.

I would just pick an AT5 palette that you are happy (enough) with and choose the first style, "AT5 Vector Map".
AT5 vector maps with RGB colours are coming in the next version of RM.

Thanks Matt. I look forward to the next version. Hopefully it'll have an AT5 version of the 6 tone 'blue to white' RGB palette as in the pic!

There won't be any need for new AT5 palettes, as it will be possible to just use the existing RGB ones - I think we might finally be able to convert you to vector :)

Maybe Lol!

Meanwhile, I'm taking a "Vector" version out with me today to work with. It sure did generate a user map faster than the raster of the same lake!