you have a great memory, that is how the rigging is done.
Using the halyard as a counter tension support is really good. When I said I was going to loosen two shrouds, what I meant was opposing pairs and your details take that thinking into account. Thanks, this is exactly what I was hoping to hear.
OK glad to help. I would not remove both the uppers (port and starboard) without a halyard in place of each (on our boat we'd use the main and spinnaker halyards). I would have no problem removing the lowers on both sides.
Hope that helps!