WTF, I see all these responses to my post, and I never received a single notification until today when the view count hit 1000. Otherwise I would have chimed in!
Anyway, when I created this post last April, I was already using an 64GB SD card for my homebrew channel apps/retro games. At that point I was looking into a USB drive for my GameCube and Wii games since the USB reads faster than the SD cards. INSTEAD of getting a USB drive (for reasons mentioned by jeannotte, THANKS jean!), I acquired a Seagate Portable 1TB external hard drive, which was just a little over $50 with shipping. Here's a link to the Amazon seller if you'd like to get one for yourself...
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https://www.amazon.com/gp/product/B07CRG7BBH/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1)
It is now September and I haven't had one single issue with my hard drive and USB Loader GX/nintendont config. The benefit to using Seagate is that they offer a free downloadable driver for Mac users so they can format to NTFS (which you cannot do on a Mac by default).
Setup was easy except for when it came to transferring files 4GB or larger on fat32 (which you cannot do on fat32, yet those larger files are some of the better Wii games in my opinion). Some people recommend splitting the file, but I tried a different solution; I partitioned my 1TB hard drive. One partition (200GB) is formatted with fat32 for GameCube games (which are never larger than 4GB). The second partition (800GB) is formatted with NTFS for Wii games. This way, I never have to split the .wbfs files. So far this configuration has performed flawlessly. I opted to go this route, because I only have a Mac, so when it comes to splitting files, I have to use Witgui. However when I use Witgui, the split files are slightly larger than 4GB, which I discovered causes loading issues. You can successfully split to 1GB files, but it just ends up being a lot of little files to manage, and I was concerned that might compromise game performance. Partitioning my drive was an easy way to dodge the whole splitting issue.
Hope this helps! I must say I'm very pleased with my modded Wii, which I feel is a far superior alternative to retro gaming than some of these devices on the market today (including the mini console series). Good luck ya'll!