This is not made obvious at the outset, but a video card with a DMS-59 connector that can drive a pair of Single Link DVI monitors cannot drive a single Dual Link DVI monitor: the DMS-59 connector doesn’t have the required signals.
The fact that each of the Single Link DVI connectors on the end of the DMS-59 Y-splitter cable have enough pins (well, holes) to mate with a Dual Link DVI cable doesn’t clarify the situation.
Of course, you can’t combine two separate Single Link outputs into a Dual Link input.
An HDMI 1.4 cable can support a single 2560×1440 monitor, but not from this resolutely low-res video card.
The Smell of Molten Projects in the Morning 
My Princeton VL1919 has the DVI-D connector, but the Sony Vaio I used didn’t support DVI. Now the Princeton is on the current Dell, but it offers VGA and HDMI. Looking at the article, DVI looked like it tried to do too many variations to really catch on. Analog, Digital, Single, and Dual? Talk about overwhelming with options…
BTW, I have (most) of the files for a Slackware distribution. I missed some files I still want (KDE Office source, mostly), and I skipped the hundreds of MB for most of the international code. (One of the MIDI packages I’m considering says it needs KDE to run.) Rather than trying to make a bootable DVD from windows, I’ll use the P2 Linux box as an FTP server. I’ll boot the Sony from a USB stick and carry on. I think/hope I can write the USB from the P2. At worst case, I’ll use pendrivelinux to make something close.
Interestingly enough, I had only one file corrupted in download–a 10M file attempted on a night when I bailed after I got 200 errors reported by the link. Not bad considering that close to a GB came off the dialup.
Sounds like you’re performing a sufficently baroque sequence of maneuvers that anything could happen, so, in the worse-worst case, you’ll learn something entirely new & unexpected!
As an co-worker once said, “There must be a harder way to do that!” Getting the Sony to write to a CD-ROM with RedHat 7 (kernel 2.4.7) is sufficiently arcane that I don’t want to try. I’m already learning a lot, some of it useful after the installation. There’s a plan C if necessary.