I've been using speaker cable for my monitors forever. AFAIK you only need a standard 1/4" cable to do connections from monitor to interface L/R outs. There is only a TS connection here (correct me if I am mistaken).
I've been running speaker cable (TS only) from my Fireface 800 outs to my Central Station and also from my Central Dtation outs to my headphone amp. I've never had a problem or any degradation in the signal...? Why is this a problem?
As far as I know, speaker cables have more noise since they aren't shielded at all, where TRS cables cancel noise out with super anti phasing technology.
I use all TRS cable with the same setup. I don't notice a huge difference either, but since my monitors are balanced and the hp4 is not, meh can't hurt.