SharePoint Online Usage Statistics with JavaScript Injection Add-in

Hi

I  want to add Google analytics to every site on our Office 365 (Classic Look" ) intranet / site collection.

The following post mentions using Google Custom Dimensions which I have now set up to track usage on behalf of my client. 

https://allcloud.com/blog/optimizing-google-analytics-for-sharepoint-and-office-365/

Rather rather hack the master page  ( see I was paying attention to Vesa and Waldek) , I am esssentially deploying the Core.EmbedJavaScript Sample with a different payload. 

In scenaro1.js I have added this globaly 

var googleAnalyticsKey = 'UA-12345678-1';  // key set up for my client 

function JavaScript_Embed() {

    loadScript(jQuery, function () {
        $(document).ready(function () {
            var message = "<img src='/_Layouts/Images/STS_ListItem_43216.gif' align='absmiddle'> <font color='#AA0000'>Daniel is attempting to inject GoogleAnalytics into this site... it could get <i>messy</i>!</font>";

 // Execute status setter only after SP.JS has been loaded
 SP.SOD.executeOrDelayUntilScriptLoaded(function () { SetStatusBar(message); }, 'sp.js');


 // Inject my function after SP.JS has been loaded
// TODO need to check/Refactor to ensure if SP.Runtime.js is also loaded before executing the function below
            SP.SOD.executeOrDelayUntilScriptLoaded(SharePointGoogleAnalyticsV2, 'sp.js');

Here is my refactored (hacked!) function based on the orginal in the above post. 

SharePointGoogleAnalyticsV2

// DW
// rewritten to hopefully use SP.SOD.executeOrDelayUntilScriptLoaded()
function SharePointGoogleAnalyticsV2() {


    // Google Analytics funtion for base tracking
    (function (i, s, o, g, r, a, m) {
        i['GoogleAnalyticsObject'] = r; i[r] = i[r] || function () {
            (i[r].q = i[r].q || []).push(arguments)
        }, i[r].l = 1 * new Date(); a = s.createElement(o),
            m = s.getElementsByTagName(o)[0]; a.async = 1; a.src=g; m.parentNode.insertBefore(a, m)
    })(window, document, 'script', 'https://www.google-analytics.com/analytics.js', 'ga');


    // custom code to seed Diminension with metadata from visits to each: Site/Page/List/Item per User
    var clientContext = new SP.ClientContext();
    var site = clientContext.get_site();
    var rootWeb = site.get_rootWeb();
    var web = clientContext.get_web();
    var user = web.get_currentUser();
    clientContext.load(site);
    clientContext.load(rootWeb);
    clientContext.load(web);
    clientContext.load(user);

    var listId = _spPageContextInfo.pageListId;
    var itemId = _spPageContextInfo.pageItemId;
    var list = null;
    var item = null;
    if (listId != null) {
        list = web.get_lists().getById(listId);
        clientContext.load(list, 'Title', 'DefaultViewUrl');

        if (itemId != null) {
            item = list.getItemById(itemId);
            clientContext.load(item, 'Id', 'DisplayName');
        }
    }

    function SPGASend() {
        ga('create', googleAnalyticsKey, 'auto');

        var userNameParts = user.get_loginName().split('|');

        ga('send', 'pageview', {
            'dimension1': rootWeb.get_title(),
            'dimension2': site.get_url(),
            'dimension3': web.get_title(),
            'dimension4': web.get_url(),
            'dimension5': listId,
            'dimension6': (list ? list.get_title() : ''),
            'dimension7': (list ? list.get_defaultViewUrl() : ''),
            'dimension8': itemId,
            'dimension9': (item ? item.get_displayName() : ''),
            'dimension10': (item ? (list.get_defaultViewUrl() + '?ID=' + item.get_id()) : ''),
            'dimension11': user.get_title(),
            'dimension12': userNameParts[userNameParts.length - 1]
        });
    }

    function SPGAError(errObj, errMsg) {
        // Optional error handling.
    }

    clientContext.executeQueryAsync(Function.createDelegate(this, SPGASend), Function.createDelegate(this, SPGAError));
        
  
}

This now compiles and deploys to my Developer site . The Google Analytics Page for my client's tenant shows 1 active user (see below) which hopefully is me.

1. Does my refactor look ok and will insert the script block(s) as per the post - Chrome Developer tools shows scenario1.js is being loaded? I am just not 100% sure the function is working correctly. Normally the analytics can be captured after a few days so I need to make sure all is well before deploying to the Intranet.
2. If 1) looks good can I deploy the the Add-in to a standard Site collection, so not just the Developer Collection
3. Will I need to deploy the Add-In to each team site in my standard site collection as essentially each master page on each Team Site will need to be running the script block.  If can I use a provisioning template to add or remove my Add-in on each Team Site?