No, Can't say I have!! Sounds refreshing!! I'm heading to the desert may have to try it.
The problem with tensile testing underlayments is the epoxy adhesive used to bond the coupon to the underlayment will fortify the underlayment as it absorbs into it.
I never seen an SLC thats got small enough grit in it to feather-edge for anything cept ceramic tile or stone. I always seem to have to finish it off using Ardex SF. Maybe it's just me from doing vinyl products allot back in the day.
See, you are using a floorcovering feather edge definition not an aci definition.
I've tried to feather the SLU for my flooring guys but I always hit it wet, and that doesn't work... Maybe if I hit it as it is setting up, but then I'd need to have one extra guy to do that, and he could only do it where he can access the slab without walking on the poured areas or he'd ruin the main body.
So I just say it doesn't 'feather edge' and leave it at that.