Been awhile since I made all my cables... it was hollow, but crushed down. Only had them in my 90° ones, too, as I recall.
Didn’t strike me as anything useful.
Once I backed the set screws out, I had full access, no struggle. I think I stripped about 1.25” wire and with a gentle twist while removing the insulation, had a nice tight spiral the easily nestled in. Insulation was just below the second set screw.
If I had to guess, I’d say these could take 10awg no problem. Uncertain if the insulation would fit or not.