Max length of IC's? Long IC's vs short SW

Regarding your general questions, there is no universal answer. It is all highly dependent on the impedance characteristics of the specific components that are being connected, as well as the parameters of the particular cables. See this thread.

In the specific case you are asking about, unless your components or speakers have extremely unusual impedance characteristics it would seem very likely that taking 20 feet off of the speaker cable length, while adding less than 8 feet to the interconnect length, would be the preferable alternative.

Regards,
-- Al

Any one know what's the max you can go with unbalanced IC's before you run into problems? Can I go 12 feet or should I try to do everything possible (unlikely) to get down to 9 feet?

As I indicated in my previous comment, there are no universal answers. The likelihood that a long unbalanced interconnect will work well depends on the output impedance of the component driving the cable (the lower the better), and the capacitance per unit length of the particular cable (the lower the better, as Ths364 indicated).

There are numerous other variables that can also come into play that are normally either unspecified or unpredictable, which makes it impossible to make a specific prediction even taking into account the specific component impedance and cable capacitance.

Your chances of success with the longer length may also be helped if you are able to have the AC power cords of the two interconnected components plugged into the same power strip, duplex outlet, or line conditioner. That will reduce the likelihood of ground-loop issues, which having long unbalanced interconnects can sometimes contribute to.

Regards,
-- Al