My preference for DXTory + spending all your money on fast disks isn't a secret. Raw uncompressed 1080p60 is going to burn around 350mb/s so a good SSD like the 850 pro is enough to keep up but you'll probably want RAID-0 just to avoid running out of space (20gb/minute adds up fast). If you're going to do the ultrawide resolutions you'd probably want a similar setup.
One trick I've found that helps for almost any capture tool when you're going to target youtube is:
- record your raw video with whatever tool you like - e.g. FRAPS at 1080p30
- convert raw video to 1080p60 (or whatever) by doubling up frames.
While the video is still "just 30 FPS" in practice, youtube gives you more than double data-rate on 60 FPS video so your final result can look considerably better in some cases. If you find block/blurry video is a problem it's worth considering even though 60 FPS has much smoother motion.
For what it's worth, DXTory will gladly capture 3x4k provided you've got the disk to put it on to. I've used it to capture 3x and 5x NVSurround and Eyefinity configurations so it should handle the ultrawide screen resolutions well too. Unless you've got more money than god, Lagarith is a good codec choice: it's lossless, low-overhead, easily converted to MP4 or whatever if your editor can't consume it natively, and it's only ~250mb/s for 4k at 60 FPS! Once you've installed the codec it should "just work" in your choice of editor. Mine (premiere) consumes it but I doubt it's an issue in others.
I'm sure you can use the codec with a number of capture tools, I'm just not familiar enough with them to comment confidently.