OP: As said earlier, 20 KHz is the minimum to prevent interference in all but strong-signal cases. The bandwidth of your signal is about 16 KHz wide, so that's 8 KHz above and below. But pick 30 KHz on 2m because that will put you on 146.55 or 146.49, which are agreed-on channels, at least in Northern CA and I assume most of the rest of the country. Maybe not L.A. On 440, check with your local repeater frequency coordinator, because different areas do "funny" things on different channels and you wouldn't want to end up on a repeater or link channel. The typical 440 channel spacing is 25 KHz.