Hello,
I've considered the "rear triangle" part of the equation, too. I assumed the longer wheelbase of the Mk6 (104" vs. 97" for the Mk3) was a big factor. The Mk3 is certainly more maneuverable. I decided to measure the distance between the rear axle to the ball. Here's what I got:
Mk3 = 40" from axle to hitch pin + 9.75" ball mount = 49.75"
Mk6 = 37" from axle to hitch pin + 6.75" ball mount = 43.75"
I was really surprised that the overhang from the axle to the rear bumper is so much less on the larger car. I also recall moving to the shorter ball mount since I didn't need the ball to sit so far from the bumper on the Mk6.
So, not only is the longer wheelbase car less maneuverable, it would seem that the shorter distance from the axle to the ball is having less effect on the direction of the trailer when I am backing? I think I have that math about right.
Regardless, I'm not rushing out right away to get that longer tongue. But it's on a long list of "to do" things... sort of toward the bottom. For now, I value the overall shorter combined length. Given that my Mk6 is 10 inches longer than my Mk3, the overall length is about the same as what I had when I towed the old 4x6 with my Mk3.
I'm expecting the wheel adapters any time now. In the mean time, I've relocated my spare tire mount and mounted a smaller tongue jack that I like much better than what I had. I also rolled-on a few coats of bed liner this morning:
Hopefully, it dried well enough before the rain came six hours later
(two hours to dry to touch, 24 hours before use).
Scott