80 - 85' will be fine for solo flight. If you have any desire to fly with others - plan on getting a set of 120', all in 90# or 100#. Just remember - the shorter the line, the smaller your wind window is. And in almost all cases, take the time to check the lines for evenness. Put all 4 lines on one stake, pull them evenly and compare lengths. Most will need adjusting. Then check again after a few flights to see if things have changed. Do not trust that "New lines are equal"!!
You can defeat the Reflex technology by removing the springs or getting another set of verticals without it. Then you can decide on how you like it set up.
If there is one piece of advice I give - Learn to "GIVE to the Kite!!". Counter intuitive I know, but pulling just drives the sail into the ground that much harder! Learn to let the kite crash. Even step forward. It takes all the power out of the sail. Much better to walk down and straighten things up, than to find a broken kite!! GIVE!!