@dsyer Having simply 2 server instances is enough to run into port in-use issues, unless, we reserve a couple of ports which is what I'm doing at the moment. Probably, a better approach would be to use a random available port which is what I was striving for as it honors the spirit of @WebIntegrationTest(randomPort = true). So yes, the setup you describe is exactly what I'm doing.
@spencergibb I forgot @marcingrzejszczak had suggested that option. That sounds exactly like what I need and I'll try it shortly.