Print position and borders on custom package

Question

I have 2 questions related to the print module
1- I have searched the web and couldn't find any indication of precise positioning options for cells (photos). When looking at the lrtemplate file, it seems like the position is driven by "bounds" and the parameters for AgMutableRect looks like (x start, y start, x end and y end). Units for bounds, imageHeight and imageWidth in this case are 72 * inch value (not sure if this is always true). I have tried modifying bounds values directly in the file and then open the template in lightroom and it worked. My question is what are "cellScreenBounds" and "cellTemplateScreenBounds" used for and what are the parameter values (and units)?
cells = {
        anchored = true,
        bounds = AgMutableRect( 85.347767253045, 77.163734776725, 805.34776725304, 797.16373477673 ),
        cellScreenBounds = AgMutableRect( 24, 21, 229, 227 ),
        cellTemplateScreenBounds = AgMutableRect( 5, 5, 55, 54 ),
        imageHeight = 720,
        imageWidth = 720,
        page = 1,
2- The next question is is it possible to have 2 outer borders, one very thin black and one large white -> on a white background? When trying from lightroom print module, it seems like the photo border is always the same color as the background color, only inner border can have a different color. Again, I have found those parameters in the lrtemplate file and  AgColor( 1, 1, 1, 1 ) seems to be white and  AgColor( 0, 0, 0, 1 ), seems to be black ... Anyone who knows what the parameters represent?
    imageBorderColor = AgColor( 1, 1, 1, 1 ),
    innerStrokeBorder = true,
    innerStrokeColor = AgColor( 1, 1, 1, 1 ),
    innerStrokeWidth = 18.084,
    lockToPhotoAspectRatio = false,
    metadataFontSize = 10,
    numLayoutPages = 1,
    oneImagePerPage = true,
    pageBackgroundColor = AgColor( 0, 0, 0, 1 ),
    pageBackgroundColorActive = true,
To give you some background, this is what I'm trying to do -> Create a custom picture package to export as a jpeg to print as a 12x12 photo. On the picture package, I want to place (precise position) a few photos that will overlap, each with a big white border around the photo and a thin black border to frame the photo (so starting from center it would be -> photo, big white border, thin black border, white background)
Thanks

Answer 1

Thank you for the reply Rob
There is no Avery template in the list that has 24 labels, which is why I was using the Custom Label
I have tried many variations trying different widths and gaps between the labels, but in all cases by the time the 8th row is printeed the printing has crept up and is now overlapping onto the bottom of the 7th row label. The third column is printing on the gutter between the 2nd and 3rd column.
When creating a Custom label it would appear that the Wizard works on Letter size Paper regardless of the paper size that the printer is set to. All my printers are set to A4 size paper.
Letter Paper is 215.9mm x 279.4mm compared to 210mm x 297mm for A4. While the width is not a problem the length is less, and that may well be what is causing the problem when the Wizard creates the labels, despite changing the Paper size to A4. But the paper size can only be changed and set to A4 after the wizard has been given the label size and spacing for margins and gutters.
In my view the Wizard should ask for the paper size and then ask for the label size settings and layout
Regards
David