I just went ahead and converted those bushings to Delrin, as well.
But, with one slight modification:
In a conventional bushing, the steel sleeve is trapped inside the bracket by the bolt, and it is stationary. The bonded rubber then flexes about that sleeve to facilitate control arm movement.
When you use poly or Delrin bushings, the sleeve is again held stationary by the bolt, and the bushing material then rotates around the sleeve.
Now, if you look at this pic, you'll see that there is a small gap on either side of the bushing. The steel sleeve protrudes from both sides by about 1.75 mm. That ensures the control arm does not rub on the bracket as it rotates.
If I were to follow that recipe, the control arm would move laterally and contact the bracket, making the whole job a moot effort.
On the other hand, cutting the Delrin exactly as wide as the bracket opening would mean binding.
I made the bushings so that there was a 1.75 mm gap on either end.
Then, we carefully made Delrin spacers that were 1.60 mm thick.
The idea was to create a "bearing" with the spacer, so the bushing would not bind.