There's something to be said for not swaging everything right away. When building a tower and setting up the guys, it sounds like a good idea to swage the terminations at the top, and I plan to do that if I ever build another tower or replace the cables on the current one. At the bottom, though, you're never sure of the exact length until the tower is raised and lowered once again (assuming it's a tilt-up of course). Once you've been through that process you know the exact length that the cables should be and you can make them permanent. If you were to calculate or guess, and have all end terminations swaged, you could have the unfortunate situation of running out of turnbuckle adjustment, needing additional parts, or having to cut and re-make the swage.
So adjustable saddle clamps have their place. I'm comfortable using them on all my guy wires, even the towing lines. Three per end. Never skip the thimble, and make the loop around the thimble tight. I check the nut tightness every time the tower is down. I once found one loose nut, but only once! May not have been tightened properly in the first place, and no faults since.
