Hey Peter,
Yes, in fact this should be the Riser Blocks Topic as it differs from thread’s creator topic
When Riser Blocks discussion once more raised up, some time ago @MikeH suggested in:
This may be a compromise that makes tabletop stiffier when rising. I would then add two more reinforcements, perpendicular to it, under the tabletop.
Seriously, in fact I try to avoid aluminium whenever I can, I prefer steel. In contrast to iron, the main steel component, aluminum cannot be found in elementary form in the Earth’s crust ( → note), but has to be extracted from Bauxite, a process which not only is highly energy-consuming, but which brings extreme environmental problems with it, even environmental catastrophies.
Also I have decades of experience constructing things using softwood and hardwood (not MDF, OSB Chipboard, or Plywood, I mean wood! 
) Many people forgot what mechanically strong things were built through the centuries using wood.