Roll cage question

[racergeo]

   
    I am helping build a 82 Firebird for Alt. class. It has a 6 point cage and the bars and the upper bars that keep you in (Pro stock cage??) Also uses a NASCAR full containment seat. It has a drivers side diagonal bar. On the passenger side it has a lower bar about 6" up that horizontally connects the front and rear hoop. Is a diagonal bar required?? We would like ease of access to electronics and dry sump etc. Thanks  George

[Stainless1]

Pics or blue prints?  That will help the guys that do cages for a living answer.