I think .033" is right. Two line is .022", not .018 which is very draggy. The unlimited FAI has no size limit, just a pull test which is likely fairly safe. I don't have a copy of that. It think it would be 2 line anyway because they don't go for the whipping that is possible with monoline. Sorry about being upside down. This is AMA. That is pretty much what we go by here in Canada. There really isn't many of us that fly speed any more.