White paint good. Easy to apply and works very well
Numbers good. last long time if you remain member of WBCCI for a long time.
You can see many approaches to numbers if you search "Big Red numbers".
The WBCCI has guidelines for number placement but there are no "Number Cops" patrolling the Airstream nation.
WBCCI purism is slowly but surely evolving to a less formal state of being. It is a comfort zone. Make sure you are comfortable and enjoy being a member of the WBCCI.
"The WBCCI Cheerleading Squad"