Wire ties are not to weak. Been using them this way for many years and have not had a problem. I did use nails like JoeJ does but found them to inconsistent on how big of a limb would cause them to bend. Sometimes when they didn't bend the mainline would stretch then I had more work getting everything tight again.
First introduced to making maple syrup in 1969
Making syrup every year since 1979
3 x 10 oil fired
Revolution syrup and max flue pan
Almost 1300 taps total with 900 on high vacuum
Bought first Marcland drawoff in 1997, still going strong.