Andy,
One thing to keep in mind is that with the Classic tonearm, the VTF decreases as the tonearm gets closer to the platter level so you do want to make sure the VTF is measured at the record surface level. The scale you have gets pretty close, but is still a bit too high to give you a precise reading. I purchased a digital scale from ebay (APTP445) that has a relatively big, flat measuring surface and I built a step with a bent credit card to measure the VTF precisely at the record surface level. It did make a difference compared to the type of scale you have. So to answer your question, yes I do measure the VTF level with the playing surface and it is critical to do so, especially if your cartridge is designed to perform optimally withing a narrow range as my Delos. .
One thing to keep in mind is that with the Classic tonearm, the VTF decreases as the tonearm gets closer to the platter level so you do want to make sure the VTF is measured at the record surface level. The scale you have gets pretty close, but is still a bit too high to give you a precise reading. I purchased a digital scale from ebay (APTP445) that has a relatively big, flat measuring surface and I built a step with a bent credit card to measure the VTF precisely at the record surface level. It did make a difference compared to the type of scale you have. So to answer your question, yes I do measure the VTF level with the playing surface and it is critical to do so, especially if your cartridge is designed to perform optimally withing a narrow range as my Delos. .