Don,
Nobody will be able to provide the data you have asked for. The best you can expect is to read the many global raves from actual owners - who adore their LPs - and have made the change.
As you have touched upon, these pressurised silicone mushrooms are carrying the full weight of not only the sub-chassis, but also the combined weight of the cart, tonearm and counterweights, main bearing, sub-platter and outer-platter - platter-mat and LP!
These weight factors significantly change the frequency characteristics… But forget about getting measurement data. The springless LP12 needs to be heard, to be appreciated.
LinnArts of Sweden sell all of the Linn bits and bobs, right up to RADIKAL level. Lennart of LinnArts considers “springless” to be the highest form of LP12.
Fair enough if you aren’t game to try the mushroom-based suspension system, but be careful not to overthink it on the blind…