Just my $0.02,
I pay $450/6 months for my 1998 E320 wagon. I have a clean record, etc. So $1200 for all your cars is not too bad.
I once had three vehicles and my insurance agent told me to get the most minimal liability limit that the carrier will allow, and then get an umbrella (excess) liability policy.
His reasoning, which may or may not apply to your situation, was that I could only be driving one car at a time so what's the sense of getting (and paying for) higher liability limits on EACH of my cars? All I needed coverage on was the car I was in if anything happened. Also, the liability umbrella would cover any claim, whether auto related or not. And finally, most homeowner's policies have this liability coverage as an option.
No one but me in my household so this line of reasoning made sense at the time.
BTW, in my market, GEICO is the cheapest agency by far.
Hope this helps.