Agreed - out of spec or not, I would tend to trust the i1pro a little more. The presumed improvement in accuracy would probably be more applicable to measuring gamut, not grayscale, but either way, a meter is better than no meter, and even an old i1 should give you reasonable results, even a some ways below 15% stim. [There has been a discussion here recently (about 20, 25 posts ago) on how to "profile" one meter using another - it might be instructive to try profiling your spyder against the i1.]
Assuming the spyder is giving at all reliable info, I wonder how you concluded cyan is off? Looking at the "delta E" row in the "Primaries and Secondaries" view, it looks like magenta indeed is the worst offender, but cyan doesn't strike me as obviously incorrect. I'd be more worried about green and blue.
Ignore the locations on the CIE chart for a moment- in the same Primaries and Secondaries datagrid view, the "delta luma" row (visible if you click the down triangle next to "Editable data") shows me green and blue are too bright. After the hue of magenta, I think that's where whatever error you have left is mostly coming from, and basically you need the CMS to make the necessary changes.
The hue of all your primaries seems reasonable. Your grayscale seems reasonable. Your white point seems reasonable. If you *still* want to get those dE's as low as possible, your priorities should probably be: making magenta less blue and/by reducing the brightness of the green and blue primaries. To do this you'll need to either experiment with the basic controls offered by the display (which can be an arsenal of very blunt weapons- you may introduce as much or more error than you solve) or start in with the CMS. No idea if that CMS is up to that task
That's the long way of saying what alluringreality said- you may already have calibrated this TV as well as can reasonably be expected with the tools and time available. If the picture doesn't look obviously wrong and it's better than when you started, then you may want to pause on this plateau awhile and enjoy it.