How do you lay up wires?

There are 2 main ways of laying up wiring used in common practice. The first is to lay the wires in a bundle keeping all wires untwisted and then tied together with lacing tape or coated Kevlar yarn. The second Method is to use a system called counter-helical winding, this teqnique involves twisting the wires around each other in oposite directions until the required amount of conductors are 'layed up'. There is a formula for calculating the most efficient lay-up. In most manufacturing workshops the formula is used to produce a lay up table, which lists the most efficient lay ups. unfortunatly i am unable to source either a table or the formula. an example of this is to use a single conductor to form a core and then to lay up 6 further conductors around this to make a perfect lay up of 7, bearing in mind all conductors must have the same diameter.