EDIT: When framebuffer-conX-type is set to Single-link DVI as described below, Hackintool crashes when selecting Patch > Connectors. It appears that Hackintool is not compatible with Single-link DVI setting. Since Dual-link DVI appears to work fine even when actual connector is Single-link DVI, it is best to leave framebuffer-conX-type setting at Dual-link DVI if you use Hackintool.
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I just learned something new after reading
this Dortania page: the DVI connector type 0x0004 that I've been using is for dual-link DVI. My DVI connectors are single-link (display resolution 1680x1050), so my framebuffer-conX-type should be 0x0200 (reverse byte order 0x00020000). I am now running with this revised connector type and am not seeing any difference in behavior. I suspect that this doesn't matter for me, because my display resolution is below 1920x1200 as discussed
here. For those with DVI displays having resolution higher than 1920x1200, you would need dual-link DVI.