auto tabbing

Yes, it's possible. You need to define this function as a doc-level script:

function autoTab(cName){
    if (event.rc && AFMergeChange(event).length == event.target.charLimit) {
        var f = this.getField(cName);
        if (f==null) {
            app.alert("Can't locate: " + cName);
            return;
        }
        f.setFocus();
    }
}

And then use this code as the field's custom Keystroke event (the name in the parentheses is the name of the field to tab to):

autoTab("Text1");