instantiating UI objects using commonJS and classes

messing around with commonJS to see if I can write more efficient code and create common UI objects using classes defined from a commonJS module.

this is how I've set it up, for example a normal label

commonJS module

function NormalLbl (e){}
 
NormalLbl.prototype.create = function(view, txt, rightPos, yPos){
    this.lbl = Ti.UI.createLabel({
        color: '#3498db', 
        textAlign: Ti.UI.TEXT_ALIGNMENT_CENTER, 
        font: {fontFamily: customFont, fontSize: 46},       
        text: txt,
        right: rightPos,
        center: {y: yPos}
        //center: {y: '15%'}
    });
 
    view.add(this.lbl);
};
 
exports.NormalLbl = NormalLbl;

then instantiate this class in a view

var surName = new Obj.NormalLbl();
surName.create(e, "Surname", labelRight,'45%');

This is working fine so far, the object is appearing on screen and appearing correctly, but...

if I want to make some changes to that instantiated object, for example if I want to change the width or font to something else, it does not allow me, I assume because its set in stone in the constructor.

So 2 questions 1. is this the best and most efficient way to create UI objects? 2. What am I doing wrong that is stopping me from editing the instantiated objects?

Thankyou ^^