>SB24 good if I get any a trigger if I want to manually >control output.
>SB 600 If I want two units that can be output controlled by >D700
>SB 28dx Could these be used in place of the SB 600s?
No! The SB-28DX has the same limitations as the SB-24. D-TTL flash control is not compatible with cameras newer than the D2 series bodies which are backwards compatible. All Nikon DSLR's from the D2 series onward use i-TTL flash control.
>SB 700 If I want to control 2 Groups, none of which could be >the SB24.
Or the SB-28DX.
>SB 800-900-910 if I want to control 3 Groups, none of which >could be the SB24.