I finished unzipping and converting a "complete" set of Turbo/PCE isos. Often a Japanese version is not included if there is an English version of a game. Some demos are included. It seems to be as complete as can be expected for commercial releases, except Daisenryaku II is missing. It currently totals 438 discs and takes up 174GB. So a 256GB sd card has plenty of room for published homebrew, hacks and translations. I just need to figure out how to rip hombrew CD games.
Opening the folder of CD games in the SSS3 menu takes 13 seconds and then navigating through them is as fast as folders of any format or size. My HuCard rom folder has 768 files, is 218MB in size and takes a split second to open. It includes translations, sound roms, hes files and misc demos.
Traditional sound roms don't usually work with the SSS3, but some do. Sound roms made by Deflemask that I've tried have not worked. Hes files don't show up in the list. Tom's adpcm example roms, which are decoded by the PC Engine's cpu and not the IFU chip, play fine. So for now, the Turbo Everdrive is still relevant for its ability to play chiptune rips. But it's still much easier to navigate through HuCard roms on the SSS3.
I'd resisted stretching out my SSS3 by trying it on my unmodified TG-16 until today. After spending a lot of time using it with my white PC Engine, I noticed a lot more static/lines/misc across picture when a CD game was loading or certain processes were happening during games of any kind. During typical gameplay segments though, there was only the minimal jailbars I described before. This PC Engine has an RGB mod which produces a picture as perfect as I've seen with various video mods performed by various people. It also has a region switch mod.
When I tried the SS3 with my unmodified TurboGrafx-16 (and SMS psu), I found none of those picture issues during processes and the in-game jailbars are pretty much invisible while the screen is moving. Knowing exactly what a stronger version of them looks like makes them more apparent to me, but they're still difficult to pick out at first, even when a game is paused.
This is why I wanted to report imperfections with a disclaimer about the setups I was trying. Many people take recommended settings as an "excuse" for problems with a product. I've already narrowed down not only a range of issues from using a cheap power supply and possibly unoptimal RGB cable, but it now seems that a jailbar fix, RGB or region switch mods are also the cause of picture quality degradation.
I'm probably going to go back to my original plan of getting an umodified CoreGrafx with stock power supply to use withe SSS3 and a Packapunch MD2 cable without audio breakout. I'll just use a TED with my modded SuperGrafx when I feel like playing SGX games.