Actually with the
UDM I would start out with a little over speed four and then after you get the product spread out 2' x 2' section increase the speed to 5 or 6. A rotary will roll the abrasives around to cut while they diminish (break down) at a uniformed high rate of speed. When using a UDM (especially with 6.5" pads) they pound the abrasives in if you start out at too high of a speed. A pad that size will not rotate easily and you are probably only getting the orbital movement. This will leave you with holograms and even with what I call stitches. It is a pattern left by the abbrasives that look kind of like a stitch pattern. Then you almost have to go with a stronger polish to cut down past them. I always start out at 4.5 and give the abrasives a chance roll and start to break down, then increase the speed and break the polish down completely and uniform.
Also, you said that you changed pads often. Just be careful when doing this. A dry pad that has not been primed will get you every time. Usually the orange pads (especially LC new ones) will hurt it but it is possible to do it with the white pads.
Lastly, make sure you not going larger than the 2' x 2' sections. Actually I would probably go with 1' x 1' and slow way down. With a white pad the risk of burning is really close to Zero and give yourself enough time. Let the abrasives distibute in your section then raise the speed and give it time to break down. With holograming (IMO) the second step is the most important. Go over it twice or three times with FPII. Also go out and get a halogen lamp or spotlight. One will do and you can get one for 5 dollars. After every pass and wipe down put the halogen up to it at an angle and check your work. Don't look directly into the lite but at the side so you are looking at the reflection with an angle. Believe me, it will show you every stinking flaw that is there.
All just IMO