The percentage of the total number of "active member", execute the TMSC modify command.

You'll need to customize to only actually modify when there is a change in state rather than because the status is above/below the threshold (as I've shown below with the simple if/else condition), but this should get you started down the path:

  foreach pn $pool_names {
     set total 0
     set usable 0
     foreach obj [tmsh::get_status /ltm pool $pn detail] {
         foreach member [tmsh::get''field''value $obj members] {
            incr total
            if { [tmsh::get''field''value $member pool-member.status.availability-state] == "available" &&
                 [tmsh::get''field''value $member pool-member.status.enabled-state] == "enabled" } {
                     incr usable
               }
         }
     }
     if { [expr $usable.0 / $total] < 0.7 } {
    tmsh::modify /net interface 1.1 disabled
     } else { tmsh::modify /net interface 1.1 enabled }
  }