Hey Pawan,

Go with Selection widget But i would recommend  > You have to override 'web' module's .js function and just change the limit given there.

----------- for odoo version 11 (web/static/src/js/fields/relational_fields.js) ------- Code where you need to change the limit ,as you can see default limit =7

init: function () {

this._super.apply(this, arguments);

this.limit = 7;
}

-- for v8 its (web/static/src/js/view_form.js)

Thanks,

Dipak