The LNB on the Dish 1000 that is used for the 129 feeds into a jack on the Dish Pro Plus Twin LNB marked LNB IN. You can disconnect this coax and run one to here from your 61.5 dish. No switches needed. Then, if you want to use the separate dish for 129, which I am doing to get a better signal than the D1000 129 LNB provides, you can aim the second dish to 129 - or keep it at 61.5 until you see a need to re-aim.
For now, 61.5 and 129 are pretty much mirrored - with minor exceptions, like the Demo channel and Pentagon, as I recall.
One coax can be run from the Dish Pro Plus Twin and use a separator (right at the 622) to feed both tuners on the 622, leaving the other coax from the Twin available for perhaps a 510 or whatever single tuner receiver you might have. Or you can run both coaxes from the DP Plus Twin to the two inputs on the 622. Separator and one coax works fine for me. Probably could also use the second coax from DP Plus Twin and another separator to run a second 622.
Actually, we took the Dish Pro Plus Twin LNB off of the D1000 and installed it on a Dish 500. Then ran my Dish 300, which had been aimed at 61.5, to the LNB IN mentioned above and aimed it at 129. My installer, who owns the company, and I think this gives better sigs on 110, 119 and 129 than using the D1000. On my Dish 300 aimed at 129, I get some TPs with sigs as high as 85, which from what I read is quite high for 129.