My trike has normal telescopic forks from a F650gs BMW the spindle is slightly forward of the fork leg.
My steering has a very slightly nervous feel to it and sometime gets in to a wobble if both hands are not on the bars. Now i dont understand to full aspect of Rake and Trail, i obviously know that a rake front end is like on a stretched chopper, with the spindle in front of the fork leg with rake to my mind should be stable.
I have ridden a couple of raked choppers and their steering was perfect, i know there are other forces involved in trikes.
I have played with front tyre pressures and found that a higher pressure is better (25psi). I had drum brakes fitted when i got the trike and one had an oval drum, this caused real problems with the steering. I fitted a disc conversion and it stopped straight away, i am now left with a very slight the front end shake.
I have had a few outfits and i know they can cause really bad front end shakes it the sidecar is setup wrong ( i actually went through a farmers five barred gate once, smashed it pieces lol).
So guys get them brains out for picking.