If you're trying multiple times without rebooting in between, that seems to be pointless from my experience. Once it fails, fully reboot your 3ds and try again
I don't know whether it works on TC's or not.
Rebooting has never worked on my 4 O3DSes before.
I can say I have tried avoiding everything possible & probable to affect Sliderhax but none of them has worked.
That's why I said Sliderhax suck.
Ninjhax is the most stable method among the HBL loading methods.
If you stuck on Sliderhax or any other, use Ninjhax instead.