Build yourself a jacking beam. The centre section in black is raised & rubber lined. The red & white stripes are the centre point. The nuts & bolts hold L shaped aluminium profiles to strengthen it. The two extra little black rectangles are locators - on the Roadster there are a couple of pegs underneath, but these are not strictly necessary.
The pad here is the centre point for the jack.
Even with the strengthening, the beam still bends slightly. The rear crossmember is wide - so plenty of space. On the Plus 4 the rear valance is deeper, and I just put the beam on it - the compression won't damage it because the beam spreads the load.
The raised section just buts up against three bolts which hold the rear valance in place.
This is my front beam when it was new.......
Note the cradles each end for the cross tube, the three buffers for the cross tube and the cushion for the towing eye.
