Might of course be wishful thinking on my part. Thanks for the advice to believe my eyes rather then my brain.
Don't feel bad, Lab has been way over sold. It was never designed for what the Lab proponents try to force it to do. Especially when they are told to convert into and out of Lab to 'fix' something they could do in RGB in the first place. It is a useful color model. It's real, real useful for defining color differences numerically. It is truly device independent but then RGB working space's are close enough and that's what is being used within LR. IF you are more comfortable viewing Lab values on the master image fine, but you can do that with an RGB working space values as well. When soft proofing, you are presumably done doing the heavy lifting and you now want to see
a simulation of the output based on paper, ink, and contrast ratio and the effect of the rendering intent on the image in context. The numbers, RGB or Lab are not really useful, the idea of a soft proof is to allow you to see the output simulation before you make a print and if you wish, conduct very subtle corrections based on that view.
A good 90% if not all corrections from the god awful images illustrated in Dan's book, fixed
using Lab could be fixed in RGB or better, just doing a better, less sloppy job of photography and raw processing (assuming any of those awful images were raw to begin with).