the PDSUL is a large big kite.
I do both. But would recommend 100 foot lines. It will give you a bigger wind window leaving you lots of room to fly her in.
in low winds though mate,the shorter lines would be better wouldnt they ?
Line length gives you different options.
Longer lines add weight & drag Many times this is offset by stronger wind at larger heights (talked about in your wind meter post)
A longer leash increases the size of your play box "'the wind window"
An example would be using a remote control car in a small room. Moving to street would give you more space. A large open parking lot would be ideal. A smaller play area will keep you busy flying you kite as well. There is no right answer on line length & I fly my PDSUL on both 75 & 100 feet. I prefer 100 because of the extra time and space it provides.