I'm trying to build a horizontal form with Bootstrap which has a row of elements on the right hand side of the form like this:

I am having difficulty getting the checkbox, label and input element to sit on a row nicely like that. This is my current attempt. I've added 'checkbox-inline' which gets things on a line, but I can't get the label to move to the middle of the line. Also, the checkboxes are much larger for some reason. Can anyone offer any hints?
The code from the Codepen link:
<form class="form-horizontal">
<div class="form-group">
<label class="col-sm-2 control-label" for="input_staff">Staff Member and Percent Share *</label>
<div class="col-sm-5">
<label class="checkbox-inline col-sm-3">
<input class="form-control" type="checkbox" name="input_staff[]" value="39">BH
</label>
<div class="input-group col-sm-3">
<input class="form-control" type="number" id="input_staff_percent_39" min="0" max="100" value="0" disabled="">
<span class="input-group-addon">%</span>
</div>
<label class="checkbox-inline col-sm-3" for="">
<input class="form-control" type="checkbox" name="input_staff[]" value="11">CC
</label>
<div class="input-group col-sm-3">
<input class="form-control" type="number" id="input_staff_percent_11" min="0" max="100" value="0" disabled="">
<span class="input-group-addon">%</span>
</div>
</div>
</div>
</form>