I don't see the benefit of using the Sherwood amps over the internal amps of the 816-K, especially in a budget speaker situation. The only reason to use separate amps would be if you have or plan to acquire speakers that are low impedence or very low sensitivity. In a budget speaker situation, most if not all mass market speakers will be 8 ohm, easy to drive and perfectly suitable for any decent receiver.
I agree with Yettitheman, crack does strange things.