Michelle,
So if you use the css rule to get your height. then add this code to the onOpen function in the about widget to fix the top placement issue:
onOpen: function(){
this.isOpen = true;
setTimeout(lang.hitch(this, function(){
this.isOpen = false;
}), 50);
var panel = this.getPanel();
var pos = panel.position;
delete pos.bottom;
panel.setPosition(pos);
panel.panelManager.normalizePanel(panel);
},