Hi,
Thanks to all who post here to help others. 

I have bought both Foam by Mail's 19 ILD and recently Sleep Like a Bear's 19 ILD on recommendation here when FBM's was not soft enough.
I would estimate that SLAB Talatech product is approximately 40% less dense, and hence 40% softer than FBM.
Sleep like a Bear is a great company providing service second to none and offers a refund, but it comes at a price.
Before ordering a 1% Queen 19 ILD I asked what the return charge would be from Atlanta to SLAB in California.
For a $172 shipping included original price, $36 would be deducted.  I was considering returning until I came up with zoning
my bed (wow, another post to explain... the answer to 12 mattresses, 30 toppers and 5 years).. I was about to return it.
Shipping, insured ground by Fedex was going to be $14, so there was a $22 restocking fee to return the topper.  Still
a bargain rather than having to eat the product if it is too soft or firm from other suppliers.
And they have a complete range from very soft to very firm, many of which others do not.

Good luck!