I debated LR vs dry with my new build...
The best solution I could come up with on how to build a stable scape with LR while keeping the die off down to a minimum would be to use a combination of acrylic rods and epoxy. You can drop whatever piece of rock that you're working on in a shallow bucket/container of SW and just drill it with a masonry bit while keeping it submerged, then just join the rocks together underwater with the acrylic rod and some epoxy to help it hold in place.
IMHO...the biggest concern with rebuilding the rockwork in an established tank would be sponges. They tend to go pretty quickly once exposed to air, and would probably be a large part of the die-off you would see in keeping the rocks out of water for even just a few minutes. The epoxy does hold well once it's dry, but I couldn't imagine trying to get rocks to balance and building a scape with just epoxy while racing the clock to keep die-off to a minimum.