In Provision IRC Services I use ':' as a separator.
Never had any problems, will most certainly use the same method for ProvisionIRCd.
This will be executed upon a successful NickServ registration command:
hadd rnicks %nick $+($5,:,$6,:,$ctime,:,$ctime,:,$live_chost(%nick),:,$live_rhost(%nick),:dW5rbm93bg==,:,$encode($rname(%nick),m))
If, for example, the cloakhost changes, all you need to do is change the 5th position.
But in the end, it all depends on your own personal preference.