Oh damn, I missed this a long time ago, but I only got this sorted out over the last couple of weeks, so maybe good that I didn't reply until now.
I had one set of Whiteline front endlinks on until recently, they got really squeaky through the winter, I don't know if they were just defective or if something else was going on.
But I digress, they kindly sent another set for me to get fitted, and we wanted to be 100% sure they were properly installed, so we put it up on the hoist, swapped the endlinks, then got it on the alignment machine so that we were under load and could adjust. There doesn't seem to be a huge range of motion in the ball joints on the whitelines, you really can't install these solo in your garage by the instructions they send. Also worth noting that the nuts on the turnbuckle come loose pretty easily and need some loctite to keep them in place.
Once you've got them on an alignment machine, get one person in the car, and have them turn the car left, right, left, right, left, right, each time checking that you have a full range of motion and that the end link doesn't bind, make an adjustment, rinse and repeat, then loosen, add loctite to the nuts, and tighten them down again. If the ball joints had a larger range of motion I don't think this would be a problem, but it seems like they only just fit with the turnbuckle aligned just right.
Right now I'm not having any problems which is a huge relief.