VOIP - transmiting data on the high priority channel

Hi there, can anyone assist me on advice on setting up high priority channels for VOIP. I have read that you assign a % of the link for high priority traffic to flow through. Is this the most effective way to setup for VOIP?? Any suggestions would be much appreciated.

VOIP can be transmitted via high priority channels: SM TOS bit - Voice gateway & VOIP boxes would have to be setting the TOS bit.
AP- enable High priority channel.

Hardware scheduling active on AP’s & SM’s.
FYI: SM’s and AP’s have to be on version 7.2 to successfully run hardware and software scheduling together.