Another key to smooth rail builds is how (and in what order) you staple the outer edges.
Start with the center of one long side with a couple of staples, then the opposite side with a couple of staples (stretch first), then the center of one curved end, then the center of the other end. Then pick a center spot between two of your stapled points and stretch staple a couple there, repeating the process where you always pick a new staple spot that is half the distance between the longest stretches of non-stapled material.
Once you have all the staples in place, then make your center cuts -- make sure you leave enough uncut material to wrap up the inner diameter of the rail (you can also cut more/deeper later, but you can't undo cuts).
Staple the inside just like the outside -- hit four spots first, then start filling in. Never staple more than an linear inch or two at one time -- always alternate sides -- that's how you prevent huge wrinkles and folds from occurring.
Start with the center of one long side with a couple of staples, then the opposite side with a couple of staples (stretch first), then the center of one curved end, then the center of the other end. Then pick a center spot between two of your stapled points and stretch staple a couple there, repeating the process where you always pick a new staple spot that is half the distance between the longest stretches of non-stapled material.
Once you have all the staples in place, then make your center cuts -- make sure you leave enough uncut material to wrap up the inner diameter of the rail (you can also cut more/deeper later, but you can't undo cuts).
Staple the inside just like the outside -- hit four spots first, then start filling in. Never staple more than an linear inch or two at one time -- always alternate sides -- that's how you prevent huge wrinkles and folds from occurring.