I have a ColorMunki Photo, which is the next-older but very similar (some say identical) device to the i1Studio. Like you, I have explored using Argyll CMS as an alternative to the X-Rite software. I had a thread about that at:
https://forum.luminous-landscape.com/index.php?topic=134572.0FWIW, I still have not tried it. Frankly, in part Argyll intimidates me--not so much the command line (I was five years into using and programming computers before I used one with a GUI), but the numerous options, switches, and permutations. Some thoughts, which you may or may not find helpful:
* The i1Studio software (currently v. 1.5.1) seems to me somewhat more accurate and flexible than the older ColorMunki Photo software (last version 1.2.4). That's not to say that you can't do better with Argyll--you probably can.
* The i1Studio software process remains a bit unconventional: print 50 standard patches, measure them, and then the software calculates a customized set of additional patches, 50 for color profiles and 100 for B&W-oriented profiles, which you then print and measure, from which the software creates the ICC profile.
* The i1Studio software process seems to produce pretty good profiles. The software seems to me pretty smart--prints made using these profiles seem (subjectively) to me far better than you'd expect from only 100 or 150 patches. I don't know how they'd compare to e.g. profiles made using conventional 729-patch (9x9x9 matrix) or 1728-patch (12x12x12 matrix) sets.
* There are reports of driver-related bridge-burning of sorts between the X-Rite software and Argyll. IOW if you install Argyll, you may well have issues trying to use the X-Rite software without changing the drivers back.
* If you use Argyll, the process will require far more patches, and therefore presumably far smaller patches. The i1Studio software produces patches somewhere around 1.0 x 1.25 in / 25 x 32mm. I seem to recall concluding that the smallest practicable patch for the hardware is about 0.35 x 0.35 in / 9 x 9 mm. AFAIK, all else being equal, smaller patches mean fewer samples per scan, and therefore at least somewhat lower accuracy. I think I'd settled on the assumption that I could use about 400 patches on a U.S. letter-size sheet--remember the device needs both white space before and after the patches during its run, and you need the paper thickness left and right to make it track correctly. But this was just my impression, and certainly YMMV.
* As already stated, the i1Studio is designed to slide directly on the paper. I don't think you could or should try to use in not on the paper. You might use a ruler or build something to guide that slide to facilitate using smaller patches.
By all means, if you go this route, please report back with your experiences. I remain interested in this approach.