What's the longest Thunderbolt cable I can use with Hilo?

Hilo-TB has been tested with standard optical and copper Thunderbolt cables. For Copper cable, one can use lengths up to 3 meters (9.8 feet) for Thunderbolt 1 or 2 and 2 meters (6.6 feet) for Thunderbolt 3. Optical cables, while somewhat more difficult to acquire, do promise operation with much longer cable lengths, up to 100 meters.