i''ll use the 1/4" i bought for the lower guy wires. the tower is 72' long. i know some of you suggested i use 5/16"., but when i went to buy the cable, they didnt have enough of that size. well, i don't think i will have a breakage issue. thats big stuff. i also went to the local welding supply and ordered a spool 250' of #6 welding cable. they didn't stock anything smaller than #4, so i had to get a hole spool of #6. $1.00 a foot [not to bad]. they wanted $2.00 a foot for #4. any way i would have a hard time using #4 cause i plan on using the twist loc plug at the base of the tower. three #4's are quite large for the twist loc plug. If I were smart I'd be dangerous