[rabbit73]

Thanks for the new photos; they tell us a lot.

I'm not a PE who could make wind load calculations, but I'll give you my thoughts.

(Note: he originally raised it by 5', but it was found that 5.5' reduced pixilation even more)

That seems to be further proof of signal layering.

The antenna is unsupported by guy wires and I saw it swaying in the wind a few inches when the winds were about 16 MPH. I fear that the pole will snap or, even worse, become a projectile during a major windstorm.

I understand your concern. How is your liability insurance?

I believe that the installer said that he has a 1.5" pole inserted about 4.5' into the originally-installed 2" pole.

That sounds conservative.

The installer said that 4 points would be needed for guy wires

That would be ideal, but it doesn't look possible.

we probably really only have two points (?) available, both on the roof.

Two points would be enough if you use braces instead of cables.
Antenna Mast Stabilization - Guy Wires V's Rods
http://forum.tvfool.com/showthread.php?t=15836

I'm afraid that I'll have to get guy wires installed. The expenses are beginning to add up to where I probably should've stayed with Comcast

That wouldn't have been as much fun and wouldn't have gotten your creative juices flowing to meet the challenge. I sometimes have buyer's remorse from the money I have spent on antenna experiments and measuring equipment, but my life has been richer for it. If you had not tried, you would have always wondered. I consider it money well spent.

Some things you might consider:
1. Mount two braces from the roof to the mast. Add pitch pads because of roof penetration; a job for a roofer
2. Use a tripod mount on the roof. Add pitch pads because of roof penetration; a job for a roofer
3. Replace the mast with one more rigid
4. Move the upper bracket a little higher and add a third bracket between the two to reduce the sway
5. Replace the 8-bay antenna with a 91XG which has, I think, less wind load
6. Hire a PE