...............If you need to increase TBM, it is better to shift weight from behind the rear axles forwards, than to shift weight ahead of the axles even further forwards. Weight centralisation should be your goal. 

The less centralised the weight, the more TBM you’ll need for stability, and the greater the TBM, the more stress on the towcar and less able the towcar is to turn the rig around corners.

The scientist in the video above did the research and testing to produce a paper on the subject (publically available, but you have to pay for it).  Having read it, the conclusion is clear:

It was found that the dominant factors affecting stability were the trailer yaw inertia, nose mass (mass distribution), and trailer axle position.  It is interesting to see that the trailer mass alone does not dramatically affect the high-speed stability, as this runs contrary to current guidelines relating to limits on the relative mass of the car and trailer.

In other words, the distribution of weight in a trailer is more important than the total weight.  If you want to buy the paper for yourself you can do so here.......

.................If you want a practical demonstration of the effect of trailer weights find a four-wheel-steer trolley and load it like so:


https://practicalmotoring.com.au/wp-content/uploads/2015/07/dynamic-trolley.jpg

dynamic-trolley

Two 20kg weights should do it.  Then push it around corners, and at a brisk pace in a straight line, waggle the trolley.   When you’ve finished re-stacking the shelves you knocked over the point will be made..............