If you want bug proof and a floor there are dozens of other tents to look at. The SL5 allows for some of us short folk to stand up. It also allows those of us that camp/hike with wet dogs a shelter that does not get muddy and soaked by the dog. For river floating its a great shelter when you can get into it all dressed in waders and wet rain gear and not worry about where the water is going to go. If you want a bug proof tent with a floor for backpacking the SL5 should not be very far up your list. The SL5 is a huge tent, and even with just the shell, pole, and stakes makes for a large load that needs to be shared between two people.
You can send your floorless tent to Bearpaw and have him sew in no-se-um mesh ground curtain around the perimeter. Then for floor protection you can use any number of ground cloth options from sil-nylon sheets to tyvek house wrap.
Or you can buy one of Bearpaws tipi tents all sewn up with mesh ground curtain installed when built. He sews his stuff one at a time as its ordered and is good to work with.
Check out the photos of his options for his pyra tents. Neither are as large as an SL5.
http://www.bearpawwd.com/tents_tarps/pyraTent.html