You should get a regulator that has at least 2 HP ports, if you want redundancy. You can buy little SPGs that screw into an HP port, that will allow you to cross check the pressure while on the surface, but would offer little in regards to redundancy while at depth since you can't see it behind your head.
If you want true redundancy, then you'll have to buy a set of analog gauges and attach them as well. But that'll mean another hose. Assuming your not doing deco or cave dives, it isn't really necessary to have a backup.
You can always just end the dive and head for the surface if the computer craps out on you. But if you want a backup, then I'd say go with a hoseless computer instead of the Cobra.
That way you could have your analog gauges on a hose and then have the computer on your wrist and not have so many hoses. Also consider that if you ever get into drysuit diving, that adds another hose. So that's, count 'em, 5 hoses; Primary 2nd stage, Octo (can be eliminated with intergrated octo), Cobra coputer, Analog Gauges, Drysuit.
But if you don't mind all the hoses, then go either way.