Automating dialogs - popup menus vs checkboxes

I have a feeling this covered elsewhere but I can't seem to find all the pieces of the puzzle.

To automate dialog settings you need to set popup menus and checkboxes. I'll use the Commit Track dialog as an example. To automate the popup menus is easy and elegant. I read the popup buttons into an array and the assign variables to each menu. Then I can check the current value and change it if necessary.

 var popupButtons = commitDlg.getElements("AXChildren").filter(function (e) { return e.fullRole == "AXPopUpButton" });

    //Assign the two menus coming out of the previous instruction to individual variables
    var commitType = popupButtons[0];
    var postAction = popupButtons[1];

   if (commitType.value.value != 'Selected Tracks')
        commitType.popupMenuSelect({ menuPath: ['Selected Tracks'] });

    if (postAction.value.value != 'Do Nothing')
        postAction.popupMenuSelect({ menuPath: ['Do Nothing'] });

I can get the checkboxes into an array the same way (at least I don't get an error) using this code:

 var checkBoxes = commitDlg.getElements("AXChildren").filter(function (e) { return e.fullRole == "AXCheckbox" });
    var consClips = checkBoxes[0];
    var renderVol = checkBoxes[1];
    var renderPan = checkBoxes[2];
    var copySends = checkBoxes[3];
    var copyGroups = checkBoxes[4];
    var insertAfter = checkBoxes[5];
    var offline = checkBoxes[6];

But then I have to use this (which doesn't make use of the variables):

sf.ui.proTools.windows.whoseTitle.is('Commit Tracks').first.checkBoxes.allItems[0].checkboxSet({
        targetValue: "Enable",
    });

Instead of :

consClips.checkboxSet({
targetValue: "enable",
});

This gives an error, and if I try

consClips.first.checkboxSet()

I get a syntax error.

Can checkboxes not be put into variables this way?