Hi Mic
No solid (fabric) inner for the Hogback. it is really meant to be a 3 season shelter that will hold a couple of inches of snow but not a winter tent
(depending on where you are of course...)
"get the biggest footprint for the weight you can"
I would think that "get the most usable space for the weight" would be a better comment.
Pyramid tents do have a large footprint but also a large non usable area.
By non usable I mean the area where you cannot sleep under .
In fact the SL5 is a classic example of that as illustrated here :

note that the bottom left drawing is the mesh inner of the SL5, the fly is bigger than that
The red line is at 8" , the minimum height in the Hogback is 15"
Hogback 51 sq feet, SL5 91 sq feet
Keep in mind that in high winds the SL5 should do better.
The hogback X pole helps to give fabric tension and support for wind and heavy rain