I have an original spec woodworker, it earns its keep cutting kiln dried oak in a commercial shop and I am fairly hard on speeds and feeds
I made a torsion box out of 25mm mdf the spoil board is also 25mm mdf with T track and various mft holes to locate vices, vac chucks etc
The whole set up is supported on 2 sides by being bolted to the partition walls in the shop with the addition of several legs made from 25mm mdf and 100 x 75 timber
I have no issues with vibration or flex the spoil board cleaned up initially with a 0.5mm pass and gets resurface when it requires it not usually due to flex or warping but because it get abused
I wouldn’t do anything different if i had to make another