A few corrections to the above...
If you have the DNAS correctly grouped (same authhash used) and they are publically listed, then if one gets to capacity, it will pass on listeners to other DNAS within the group until the listener gets a valid DNAS (assuming that there is one which has free capacity).
And you should always be using DNS entries for the DNAS (configured via destip which i hope the Centova software supports setting) as that makes life far easier if you need to add / change servers around instead of going with IP specific urls (which have not been the recommended way to do things for years now). It also makes things far better for the listeners - which all to often seems to be forgotten about by a lot of stations.
And technically, you could use the v1.x DNAS with the now deprecated v2 sc_trans if that is so wanted - it still allows you to have the autodj functionality. Though, it doesn't help when neither of those pieces of software have any official support now.