Audiojedi,
I don't quite understand why you need washers to mount a Vector. I had a Vector 3 mounted on a Verdier turntable and had to extend the arm up high enough to align properly, I mounted a small wood block with carpet tape under the micrmeter to adjust VTA. The Vector has a long mounting post that should be adaquate to mount on your Rega. I also used a Shelter 90X and a Denon 103 cartridge with two counter weights and had plenty of adjustment left. One thing about The Vector is the bearing has a small shoulder around the dimple that the point should mate with. You have to be carefull that the point is not resting on the shoulder and is inserted in the bearing properly. This could change your VTF.
I don't quite understand why you need washers to mount a Vector. I had a Vector 3 mounted on a Verdier turntable and had to extend the arm up high enough to align properly, I mounted a small wood block with carpet tape under the micrmeter to adjust VTA. The Vector has a long mounting post that should be adaquate to mount on your Rega. I also used a Shelter 90X and a Denon 103 cartridge with two counter weights and had plenty of adjustment left. One thing about The Vector is the bearing has a small shoulder around the dimple that the point should mate with. You have to be carefull that the point is not resting on the shoulder and is inserted in the bearing properly. This could change your VTF.