Mike,
Apparently the specs are exactly the same as per Obsession scopes, so based on the Obsession specs, the 20" f/5 has a focal length of 100", ie 254cm, which is EXACTLY the same as was my LX200. In other words, same magnification as before.
HOWEVER, as the 20" will be able to handle up to 1000x on a regular basis, I will, as you suggest, have to get some shorter focal length Ep's. I might have to start by making Matt an offer for the return of my 13mm T6 Nagler.
Other specs:
2" thick primary mirror, with 96% reflectivity
3.1 inch secondary mirror, with 98% reflectivity
11 lbs upper assembly
100 lbs lower assembly (25 lbs with wheelbarrow handles)
Height at zenith 8 feet
limiting stellar magnitude 16.5
Rayleigh Resolution limit 0.27 arc seconds
Lower assembly dimensions: 31"x29"x25"x27" (huge!)