Well, I took the Vaico front bush assembly apart, and it consists of a front washer/rubber combo (front stop), the main bush (in the wishbone) which sticks out the front (only the tube), and out the rear similarly, with the addition of rubber along the outside diameter integrated with the bush (rear stop). Finally, there is the rear metal washer.
The washers were pressed into the tube, but they only go a few mm into the tube, so adjustability seems small. What seems to matter is space between rear bump stop rubber, and whatever solid surface you're going to have in the back (the lightly pressed in washer in this case). The only thing you can adjust in the front it seems is installation of the console, front and back, on the car. The console has to be placed far back enough so that the front washer/rubber stop can be against the subframe, and when all screwed together, there is the specced gap between it and the wishbone. But it might be that you have to push the console back to get to the min. in the front, but you can't, because you'd end up below the min. spec in the rear. In that case, you'd have to move the whole console back, allow you to maintain the rear gap, while increasing the front. Oh brother! I wonder if anyone does that, heh.
It also seems to me that the tube sticking out the front is what's going to hit the front stop washer first, and not the wishbone. I wonder if that's by design. If so, the main bush would take the load, and only when the wishbone would move further forward (that's a lot of bush ruuber to deflect), it (by design) would touch the front stop washer's rubber, which then would take some of the load. Seems a bit odd to me, and also, it seems like, then, if you press the front stop washer/rubber into the tube, so that the metal part of the washer touches the tube, if you do not have the required gap between the washer's rubber and the wishbone, you're out of luck! Because even if you set the specced gap with the console, etc., properly, when the wishbone moves forward enough, the washer/rubber will get pressed into it until it touches the tube, and when the wishbone moves back, it'll 'take' the washer/rubber with it. It therefore might not matter what front washer rubber to wishbone gap you set in the front, because the limiting factor might be how far out the main bush tube sticks out! Basically, if you push in the washer/rubber into the tube until it hits the tube, and you don't have the min. gap between the rubber and wishbone, you're outta luck!
Clear as mud? How's my burning-the-2:30am(here)-oil analysis?