i had a friend do his miata on his own, and he and i are planning to do my fairlane by ourselves
but i hear it is difficult to get right
the guy who has been working on my fairlane said to leave it open a couple inches between the windshield and the top and pull it tight like that. then when the top closes for real, it will be nice and tight.
but heck, $600 buys 3 more tops, so for the same cost of getting someone to put it in for you, you can buy 3 more tops and try it yourself 4 times. i bet you'd get it right before the 4th try.
on a sort of related note, i'm recovering the seats in my fairlane right now