Do you have any knowledge as to why the Tarp tents do not seem to sag ?I do...
Tarptents sag just like all nylon and in particular silnylon tents, it just that they are easier than some to pull taut (once they sag) and I have spent years telling owners off for not setting up their tents correctly.
"If your tent does not look as it does on the TT web site , it isn't the tent fault..." is my typical irritating to some but nevertheless true comment.
Here is a good example :

this has been posted in various forums to show how bad Tarptents are.
Problem is that owners like me that know how to set them up can spot immediately that it is just a badly set up shelter....
BTW, tent poles will tend to keep the shelter taut a bit longer than trekking poles because of the bend in them keeps them in tension.
However a Scarp will sag and remain sad looking if you let it be.
Sad Scarp :

Happy Scarp :

it would take a typical TT owner 30 sec to go from sad mode to happy mode.
Note that there is frost on top of the happy Scarp.