do you have a QOS service level agreement with you provider? if so , use their recommended classes,
if you do not, they may remark all your traffic back to 00
QoS is an end-to-end deployment, simply marking traffic on your router does nothing for QoS,
you need to trust, mark and prioritize packets from the source to the gateway within your trusted domain.
and remark packets from sources that you do not trust.
marking BGP packets, if they are generated from the router itself, may be a problem
"If you're good at anticipating the human mind. It leaves nothing to chance."