If you are looking to set a specific weapon without cycling to it, try /equip or /equipset. the command for cycling weapons for a macro would be:
Code
/con gs c toggle mainweapon
Code
gs c toggle mainweapon cycles main weapons in the list you defined below
gs c toggle subweapon cycles main weapons in the list you defined below
these cycle through weapons you define in
Code
mainWeapon = M('Crocea Mors', 'Naegling', 'Maxentius')
subWeapon = M('Ammurapi Shield', 'Machaera +3', 'Kaja Knife')
As far as I can tell there no way to set a specific weapon without cycling through the list. It could be added to the lua.
You also may need to toggle melee so that it locks your weapons, otherwise the lua may swap weapon depending on what is set in mainWeapon.