Rex Bridge is likely to become the contract, the valuation of the hand is again counted according to the Contract Bridge practice. A second major difference is the possibility to bid at level 8 and 9. This may seem awkward, as it would take 14 or more tricks to make a contract at level 8 or higher. Even if the declarer takes all 13 tricks, he will still incur a one trick penalty. However, the payment for a made grand slam can still outweigh several doubled penalties. How many depends on vulnerable or not. Consciously bidding higher than what the cards says
The Bridge World the magazine has periodically polled experts on various bidding treatments and conventions in order to develop a unified system of bidding known as Bridge World Standard. There have been five versions of the system with the latest revision being the 2017 edition. Bridge World Standard has evolved with the practices of North American experts and, similar to the Standard American Yellow Card system promulgated by the American Contract Bridge League, is offered as a system "for use by impromptu or casual partnerships, and as a basis for discussion by those who wish to formulate their own system." The Bridge World