My breaker panel is a Square D, Homeline, 30/30 type with a 200 amp supply.
All breaker spaces are in use. Being a 30/30 type I cannot replace some of
the existing breakers with two gang, 120 volt breakers. Is this correct?

I'm assuming I need to extend my existing breaker panel with a second small
panel. Should this be wired to the main feed or can it be wired to the buses
inside the existing panel? The second would be easier for me. There will be
five extra circuits, some twenty amp, some 15 amp. Do these five extra
circuits need to be divided among two phases or can I put them all on one
phase? An additional panel would be small and would have to be placed below
the existing panel. Is this a problem for inspection?

I appreciate all the help I can get.

Peter.