I use the same WBBB, and weigh 215. I used 2 sections of chain link top rail, cutting them at 7 ft 6 inches so they would store better in the garage, and they also match up with the 7 ft 2 x 2s. Top rails are 1 3/8ths and have a nice end cap that has a place to clip in the carabiner, if you use them. No need for a coupler, as they slide together. Cost for the top rail is about $11 each. I am just now posting pics of mine in the other thread.
ETA: I used 10 ft of amsteel for my tension restrictor. That is, it was 10 ft from end of loop to end of loop. I had them already, and they worked out fine. I suppose there is really about 11 ft of amsteel there.
Last edited by olzeke; 05-15-2012 at 18:28..
Reason: added rope details, and spelling.