Me too. But I bought an Ebay Techstream Diagnostics tool to be able to read the sensors and solenoids.
Part of the tool is also an active test where you can set the height of a wheel separately. Everything works fine, all solenoids open en close when activated, height readings also reflect the up and down movement. In the tool is also an option to give an offset to a sensor in case it's not perfectly mounted. To be able to give such an offset the tool asks you for a service manual value and an from that you can put in your adjustment.
I've been searching for a proper RX300 manual where I can find these values, but no luck so far. Also it would be nice to know what the height sensor must indicate when the car is in LOW, NORMAL or HIGH position. Guess I'll go for the option mentioned to disconnect the battery when I have set the car 'straight' in NORMAL. Or has anyone a better suggestion??