Adjusting Tab Height

Hi. I'm working on an application with tabs, and I was trying to adjust the height of the tabs so it doesn't extend quite so far into the window of the phone. I know there are properties called height and tabHeight, but I'm not sure which to use or where to put it. This is my code for creating the tabs:

function ApplicationTabGroup(Window) {
    //create module instance
    var self = Ti.UI.createTabGroup(),
        Home = require('Home');
        Settings = require('Settings');
        //self.backgroundColor = '#F5C400';
        //self.activeTabBackgroundColor = '#67EB15';
    //create app tabs
    var homeWin = new Home(L('home')), 
    settingsWin = new Settings(L('settings'));
 
    var homeTab = Ti.UI.createTab({
        // title: L('home'),
        icon : '/images/header_home0.png',
        window : homeWin,
    });
    homeWin.containingTab = homeTab;
    self.addTab(homeTab);
 
    var settingsTab = Ti.UI.createTab({
        // title: L('settings'),
        icon : '/images/header_settings0.png',
        window : settingsWin,
    });
    settingsWin.containingTab = settingsTab;
    self.addTab(settingsTab);
 
    return self;
};
 
module.exports = ApplicationTabGroup;

I've tried putting height : '5%', within the creation of the individual tabs (after the icon specification), and I've tried putting self.tabHeight='5%' after creating the tabGroup and before creating the actual tabs, and I've also tried doing this:

var self = Ti.UI.createTabGroup({
height : '5%'
}),
        Home = require('Home');
        Settings = require('Settings');

but nothing seems to be working. Thanks in advance for help!