Very interesting Tim, sorry to see that you're having problems with root rot, but glad you could salvage Torrid Zone. Do your think weevil larvae ate the roots, or is the soil/weather too moist? Seeing the mild Zone 8 in your profile, might that have something to do about different plant growth and mounding? I'm in Zone 5, quite different.
I like heuf 'Minutum', it's available & inexpensive so it's on my order list for 2018.
My heuf 'Gold Bug' has been with me since I've been in my current location, 30 years. I grew it for many years in a large plastic planter on my deck, until the planter cracked. Here it is in that old planter, I count 11 rosettes. Photo from early spring 2002.
Summer 2010 they were moved to a new planter, this photo from April 2017, 2011 with 10 rosettes starting to start into spring color.
Compare with this photo 5 years later, end of March 2016, just breaking out of dormancy and into spring color, I count 22 rosettes. Each year I do a spring cleanup on them, de-moss and weed, add fresh gravel mulch, etc.
The following year, May 21, 2017, a view showing Gold Bug in active growth, from this low angle can't count the rosettes, red S. 'Brock' on the right.
Searched my unprocessed photos from 2017, found an overhead view, I count 25 rosettes, could be a few more snugging down under the enlarging rosettes. Now that they're filling in, perhaps if they get overcrouded they'll start mounding. Might be a good reason to thin them out a bit and make a few rosettes available to domestic USA forum members.
Photo from June 1, 2017, again with red color S. 'Brock' above.