I would strongly suggest doing ack/nak – without that there is a good chance you could eventually have a lost message.
Also all starting multi-site. You need to give some planning to this direction.
I have been involved in multiple site integrations for nearly 13 years and have a fair amount of experience.
There are other posts on clovertech regarding some of the particulars related to the concept of multi-site utilization. It would be worth your while to research that further.
One important decision you need to make is regarding the handling of what may now be ‘global’ objects (formats, Tables, Tcl procs, etc.).
Do you keep multiple copies (one in each site where required) or do you have a global place to keep one copy? If you are on Cloverleaf(R) 5.6 or later, there is a master site to assist with going the global object route. If you are pre-5.6 this still can be accomplished via soft links but you need to decide how that will be deployed.
There are other considerations as well.
Doing this analysis early will save a fair amount of pain versus discovering the issues as you progress.