I'm no engineer but I'm pretty good at what I do...
With that being said, when I see most of the girdles that are out on the market to me the only thing that your stabilizing is the main studs. There is no "triangulation" going on with the main cap and the block.
Now.....If there was a bolt going through the girdle and it threads into the top of the main cap itself.....now you have triangulation and stability.....everything is tied together and sound.
It seems like most caps break....like the ones that I pictures above....at the 8 o'clock position. A 5/16" drilled hole at the 6 o'clock position is not a week area. Many of the after market caps already have a taped whole for a slide hammer to aide in removal.
This is just my