A couple more quick cage questions:

The GCR states "a maximum of two gussets per rollcage joint are allowed". What is the definition of a rollcage joint? If 3 tubes come together in one spot how many joints is that?

The GCR states in 9.4.2 J "In order to provide a secure seat back support a section of tubing equal to the rollbar shall be installed horizontally from the main hood upright to the diagonal brace. This tube shall be no higher than shoulder height."

In cages such as the miatacage dot com that only have one horizontal bar what is the optimal/legal height to install it so it can satisfy the seat back support *and* harness bar rules? The bar needs to be below shoulder height for the seat but how far below...since lower = more chance of compression injuries I don't want a cage that a taller person than me cannot be safe in either....

Also...if you run an FIA seat and thus do not use the cage for any seat bracing does this rule even apply?