After more research and thinking, I will be swapping out my Pushmatic 20 space load center for a new one. Happily, my service is already 200A so I don't have to change the SE conductors (3-wire, 3/0, copper).
I'm considering the Cutler Hammer CH 42/42 and the Siemens 40/40. Both have a copper bus. Apart from the 2-circuit difference, why would you recommend one over the other? I have heard lots of good things about the CH, but have less info about the Siemens load centers.
Also, I will need to change the meter base and service entrance conduit. Are there any good resources showing how the meter socket and panel grounding need to be done? The old SE conduit is steel, but I will be replacing it with PVC. So should I be swapping the grounding bushings for grounding locknuts? Seems like a metal bushing on plastic pipe wouldn't do anything...
Also, does the PVC need to be Sched 80 or will Sched 40 work. My Code Check book says 80 is required if the SE is "subject to damage". Does conduit running along the side of the house fall in that category?
Check out my diagram and tell me if I've got it right...or if I'm close!