It would seem to be prudent to go ahead with a single clustered
instance, not a stand-alone instance to deploy the application so that
it is ready for expansion to multiple instances if needed. There would
not be any advantage to using a stand-alone instance in this case. While
using the DAS to run the application is a possibility, this may
interfere with having your DAS isolated from the production network.
Often, the DAS is setup on its own network to isolate it from the
production servers.
Tom