Question on conforming

Interesting situation today. The Viking shieldwall had the very last element trailing by one basewidth, ie it was front right corner to back left corner contact with the group. The Saxon advanced a Psiloi to touch the far edge of the TZ of the last element of the group, though most of the element lay in front of the trailing element. Now it's the Viking turn. I want to reform his line and engage the Ps, preferably at the end of the line. But when I read the rules I was struggling to find the exact moment that conforming occurs. Is it at contact or at the end of movement?

If it is at the end of movement then I would follow this route:

- Advance the solitary element to contact. Advance the group alongside to reform the line. Slide the Ps laterally to line up with extreme end of the line. 

If it occurs at contact then I would have to follow this route;

- Advance the group to contact. Force the Ps to conform to the group. Then advance the solitary element back into line, "overlapping" the Ps (though it doesn't actually matter).

This would place the Ps aligned with the second last element of the line. This is not a deal breaker and better than the following outcome:

- Advance the solitary element. This now has to slide to conform to the Ps and is overlapping the last element of the group, which is also in TZ making manoeuvre a right old mess!

So learned friends, do you conform at contact or at the end of movement? 

Cheers

Jim