Also, the more angle you introduce to the the set up, the more your lenses will be off of their focal plane.
I have a 1271 that I just mothballed and for about 6 months I had it set up so that there was more than the usual angle of incidence.
What I found was is was very difficult to have sharp focus between the top and bottom of the image.
The solution is to install Moneyasses modification. Do a search on the forum for a link to his web site, which has a PDF file for reference.
It's not difficult, but block some time aside to do it. Basically, it involves removing the lenses and the lens spacers and installing allen bolts that will allow you to continuously vary the projection angle of the lenses.
You'll need to do a pretty substantial re-covergence afterward.
Having said that, once I had the focus dialed in, the image was sharper than ever.