And use eyelets! I cheated on my 24.5" Scientific P-40. I thought, Meh! How much pull can there be?
Second flight I felt something go "Pop," and the plane lunged for the ground!
I barely got enough up into it to fly the tank out. After landing I discovered the neat little loop I put in the up-line pulled out within the sleeve, and stopped pulling once it was cinched down on the line clip. The down-line hasn't pulled out yet, but I had to re-do center based in the up-line now being a 1/2" longer! Those lines will be cut down and remade for smaller models...with eyelets!
I bought my crimping pliars from Hobby Lobby. A nice, pretty, pink round trip needle-nose pliars for only crimping sleeves. Later, same lines, but fresh, with eyelets and copper tubes. Not one pullout, even when slinging my BHM Mosquito around (twin .074 Norvels... not very light).