I can't really see how the track rod ends could be wrong, (where did you buy them ?) as there are only two kinds used on Xantia's, a small threaded version for most Xantia's and a large threaded version for some large engined models like the V6, and they're not interchangeable.
The ones I fitted to my V6 are Lemforder brand supplied from carparts4less.co.uk:
http://www.carparts4less.co.uk/cp4l/c/C ... c01&000349" onclick="window.open(this.href);return false;
(They also have the smaller threaded version)
From memory there are about 5 threads exposed on each track rod end with the correct wheel alignment, which means over 80% of the thread is hidden within the track rod shaft.
How exactly are you determining that they are currently toeing in ? It's very easy to get sucked in by optical illusions when trying to judge it by eye. I was convinced mine were toeing in before I built the laser gauge shown in the linked thread, but much to my surprise it measured spot on at 1.5mm toe out. (0-3mm toe out is acceptable)
I don't think its possible to judge by eye even approximately, nor with a measuring tape, you're really going to have to measure it using a technique like the laser one from the linked thread - there is no "quick and rough" method of checking it, because most DIY methods will have a margin of error 10x greater than the actual desired toe out. (Trust me, I've tried a few other ways and none of them are remotely as accurate or repeatable as the laser method described by thorter, which is pure genius in its simplicity and accuracy)
Another thing to keep in mind is that it doesn't take much adjustment of the threads to effect a large change in toe out. A single turn of the thread on one side is a change in toe out of 4mm, so a single turn on both sides together is a 8mm change - a huge amount compared to the desired 1.5mm toe out. One turn on each side is enough to swing from massive toe in to massive toe out.
The only problem with thorters method is that while it measures the toe out very accurately it can't determine the absolute steering centring - this you'll have to do by driving on flat level road and checking the steering wheel for centring.
Since you've had the steering rack out its possible that the mounting position is not exactly right, or that the steering wheel is not correctly aligned relative to the pinion. I would probably start by very carefully equalising the number of thread turns visible on each track rod end, check the steering wheel centring by driving on flat level ground, then if its more than about 20 degrees out remove the steering wheel (carefully, watch out for air bag connectors, check relevant threads in the forum) and reposition it on the spline to get it as close as possible to aligned when going straight ahead.
Then adjust the toe out using thorters method (apart from a couple of cheap laser pointers everything else can be made from scraps) then take it for another drive - if the centering is just a few degrees off make a very small change to each track rod end - 1/8th turn shorter on one side, 1/8th turn longer on the other etc until the steering is dead ahead driving on flat level ground then double check the toe out is still correct.
This assumes left and right tyre pressures are balanced, the test road is level, and front tyre wear is even.
. That heat shield looks awkward and fiddly , tempting but probably best not to omit it on reinstallation I guess.
