I attach my Oplux and Amsteel bridges a little differently, but similar. To re-create his bridge, get 5’ of Oplux.
The size of the amsteel continuous loops you need depends on the thickness of the bridge loops and how many wraps you want to make around them - I make 2 wraps around medium thickness loops and 3 wraps around Oplux bridge with about a 14” continuous loop - I start with 56” of amsteel to make a 14” long loop. You have to make 2 of these for this design so a minimum of 112” of 3/16” amsteel. You’ll have to adjust according to what you want. Probably a good idea to get some extra as trying to attach these loops when they’re too short is a major pain!!!