You can dynamically override the GAM Ad Unit by setting the data-unit DIV attribute.
For example, suppose the UI has configured a slot named top-banner with the GAM Ad Unit set to leaderboard
Normally, the following DIV would be added to the page
<div class="htlad-top-banner"></div>And that DIV will load the GAM Ad Unit named leaderboard, since that is configured in the UI
In order to override, use the data-unit attribute. For example to load a GAM Ad Unit named sports/baseball/leaderboard, use the following HTML
<div class="htlad-top-banner"
data-unit="sports/baseball/leaderboard">
<div>