The second option would certainly be easier to pull to your display, as an HDMI cable needs at least a 1-1/2" conduit and pulling a second one in with one already there would probably be easiest with at least a 2" pipe (unless you are just pulling through a ceiling space and walls all the way there). I'd probably do an HDMI-to-HDMI cable and an HDMI-to-DVI adapter from the 990 to the display, though, just as future-proofing for that long run. That way, if you replace the 990 later with something that uses HDMI instead you can just drop the adapter out of the way and retain that long cable. (You could use an HDMI-to-DVI adapter later, but due to weight issues it's must easier to use a DVI adapter and an HDMI cable than the other way around since the DVI adapter can be secured in place with the set screws.) I'd also get cables with as little extra length as possible, as the HDMI spec (like the DVI spec that it borrowed from) is capped at 15 meters. Exceeding that length (the 50 foot run you see so much of) gets into uncharted territory, and for a cable that length to work requires oversized conductors and good terminations (or a booster of some sort, of course). If you can get by with a 30' cable and some 3' to 6' cables at the 990, I'd certainly lean toward doing that.

What you might do is pull one 30' HDMI cable in and test both approaches - go straight to the display from each source to test how they work, then use an adapter and a short DVI-to-HDMI cable to test running through the 990 for each. My suspicion is that as long as that long cable works, you can use the 990's switching and save yourself the hassle and expense of a second long HDMI cable.