Fitting front wheel and torquing up spindle nut

James - So is the shoulder on the spindle hard up against the bearing cover when the spindle nut is tightened ?  When it is all tight to the set torque does the wheel rotate freely and is the rim central in the fork sliders ?  You don't specify which type of forks ie pre-64 = narrow ; post 64 = wide.  If it doesn't spin freely when all is tightened then make sure that the bearing lock-ring and felt washer are correctly installed and tight in the hub.  It is usual for there to be a small gap between the left-hand slider and the bearing cover,  Apply the brake and compress the forks against a heavy object to settle the sliders and then tighten the pinch nut carefully !!  Good luck, Howard

Surely there should be a gap. But it will be on the larger diameter of the spindle. The shoulder of the spindle butts against the spacer which in turn sits against the bearing so it's all tight against the RH fork leg. And then the left leg floats on the spindle for alignment until you tighten the pinch bolt. If the left leg is hard against the spacer then it's the wrong spacer.

And not a lot of people know this - but there are lots of Dommies running round with the pinch bolt tight - but not actually gripping the spindle.  Put the ball of your hand on the end of the spindle and often you can pull the spindle sideways.  Does it matter?  Perhaps only with a sidecar?

... many years ago I had a Domi 99 whose pinch bolt lug had been broken off by a previous owner (I assume). I didn't see anything wrong with its handling although maybe I wasn't experienced enough to notice! For a solo I don't think it does a lot.

If you have a look at https://www.youtube.com/watch?v=6ZvVmUIl13g
You will see why there is that gap.
Explained by others above I know but sometimes a picture helps.

A stainless axle I bought had a slightly oversize section that fits the nearside slider. I had to open out the slider bore with abraisive to fit.