In 2015 I made finite element modelling on a 2005 PLUS 4 chassis making assumptions on the weight distribution but checking that I got the same measured weight on the wheels than during the MOT.
It could give an idea of the structural deformation and stress in the chassis and particulary in the girder which is a critical element.

For example when you lift the car under the first cross member ( see picture :point de levage) the maximum constraint is 4.84 daN/mm².

The maximum is 6,26 daN/mm² (von Mises constraint) when you lift the car by the rear croos member.
Minimum is on front cross frame (3,11 daN/mm²).

I don't know what steel is used by Morgan, but with a 36 daN/mm² elasticity limit steel you get a safety coefficient of 6.

You can use any cross member without stressing the chassis, some are better than other.

[Linked Image]

Regards
2005 PLUS 4