A partial answer you don't have DPP LNB's if you have single or duals on your dishes. A DPP TWIN was made for dishes such as the 500 or original 1000. All that really means is band stacking was used instead of voltage switching used on Legacy LNB's (original DISH or Directv LNB)
DPH42 takes DP LNBs and converts them to work on hybrid systems giving correct frequencies and satellites.
If you can see 61.5 and 72.7 you only need 2 dishes to get all of DISH's programming. 61.5 & 72.7 will work with your existing Hopper 1.
Sorry if I called my LNBs by the incorrect name. I've attached a picture to show you what type I use.
For the longest time, everyone where I live only tuned in to 119. Eventually, they started to add a second dish for 110. Then someone got smart and figured out that you can actually just make an "L" bracket and add another LNB to the dish for 119 and pick up 110 also with just one dish. I never tried myself, but I was told that 129 is too far below the horizon to get a good line of sight, so as far as I know, no one uses it.
When I first set my system up, I did a ton of research into seeing which satellites I should use in order to get HD programming. At that time, it appeared that 61.5 was the one to use, so I think I may have been one of the first to even try and see if it could be done. I was able to pick it up, but unfortunately, very shortly afterwards, DISH switched over to using a new satellite at that location which was pretty much just spot beams (which of course I'm nowhere close to being under any of them). Then I switched to using 119 and 110 on one dish, and 72.7 on another. That's how I've been set up ever since. Like I said though, it appears that I'm now going to need to switch back from 72.7 to 61.5. I haven't done a comparison using the List to see if I would be better off just looking at 72.7 and 61.5 instead, though.