Correct bootstrap3 way to give padding on grid - twitter-bootstrap-3

Question

I have four inputs in the same row and one of the input is conditionally visible by clicking "Click" button.
So if all four inputs are visible, the inputs datepicker1 and datepicker2 are sticked on the inputs above.
What is the correct bootstrap way to arrange and beautify the distances between the inputs?.
Gutters are not available on bootstrap 3.
<div class="col-md-3">
<select class="lookup-type-select form-control" name="created_lookup_type_1">
<option value="range">Range</option>
<option value="range__exclude">Exclude Range</option>
</select>
</div>
<div class="lookup-value">
<div class="col-md-3">
<select name="created__1_0" class="filter-input shortcut form-control" id="id_created__1_0">
</select>
</div>
<div class="col-md-8 row custom" style="display: inline;">
<div class="col-md-6">
<div class="datetimepicker input-group start-date date" data-date-format="YYYY-MM-DD HH:mm:ss">
<input class="filter-input form-control" name="created__1_1" value="" type="text" id="datepicker1" placeholder="From">
<span class="input-group-addon">
<span class="glyphicon-calendar glyphicon"></span>
</span>
</div>
</div>
<div class="col-md-6">
<div class="datetimepicker input-group end-date date" data-date-format="YYYY-MM-DD HH:mm:ss">
<input class="filter-input form-control" name="created__1_2" value="" type="text" id="datepicker2" placeholder="To">
<span class="input-group-addon">
<span class="glyphicon-calendar glyphicon"></span>
</span>
</div>
</div>
</div>
<div class="col-md-3 row month_only" style="display: none;">
<div>
<div class="datetimepicker input-group start-date date month_only" style="display: none;">
<input class="filter-input form-control" name="created__1_3" value="" type="text" id="id_created__1_3" placeholder="Month">
<span class="input-group-addon">
<span class="glyphicon-calendar glyphicon"></span>
</span>
</div>
</div>
</div>
</div>
<button type="button" class="btn remove-button">
<span class="glyphicon glyphicon-remove"></span>
</button>
<button onclick="myFunction()">Ckick</button>
<script>
function myFunction() {
if (document.getElementById('id_created__1_0').style.display != "none") {
document.getElementById("id_created__1_0").style.display = "none";
} else {
document.getElementById("id_created__1_0").style.display = "inline";
}
}
</script>
Jsfiddle example
Should be like the following pic