One of the most comprehensive, creative, and clever mods I've seen posted in a long while!
Now as to using the existing LNBs...
- you might come up with something creative with their spacing
- the diseqc switching in the head would probably work as-is
- inside each horn/throat is probably a metal vane; file it off to convert Circular to Linear
- but...
- some DishNet LNB assemblies pull a lot of current, so check before starting
- you're still stuck with the wrong LO frequency (it's DBS)
- DishNet hardware will be bandstacked, so be prepared to deal with it
The only mod I might add to your excellent work, would be to find a shorter LNBF.
That would save a bit of effort.
If you'll measure the existing feedhorn length, I'll check some short LNBFs and see if any would fit.
Some of the smaller ones are SatelliteAV single and dual output, and his new PLL model.
I have all of those on hand.