My current install consists of an HR-24 w/AM21 , an HR21-700, and an original HR20. The HR20 is showing signs of a failing hard drive, so I'm considering replacing it with an HR-34. So, here's the question. If I swap the HR20 with the HR34, I'd have 9 tuners vying for only 8 available (single wire SWiM dish). Does it make sense (or even work) to just tell the HR21 to be a single tuner, or should I go ahead and replace it with a C31? Thanks!