Answered it myself, simply by thinking: mobile first!
<div class="col-lg-3 col-xs-6">1</div>
<div class="col-lg-3 col-xs-6 col-lg-push-6">5</div>
<div class="col-lg-2 col-xs-4 col-lg-pull-3">2</div>
<div class="col-lg-2 col-xs-4 col-lg-pull-3">3</div>
<div class="col-lg-2 col-xs-4 col-lg-pull-3">4</div>
Get them in the order I want on the tablet first, then push/pull them in to position on the desktop.