@Tortue Viscoset headset bearings are sealed. Only grease recommended is on the cups to aid installation and a "waterproof grease" on the crown race seal and top cover seal to "keep everything turning smoothly".
@cpml123 I've only had one ride on the S40 since installing the Viscoset headset. My initial impression is a reduction in the tendency for the front wheel in a slow speed tight turn to want to tuck into the turn.
I also have an impression of slightly less handlebar input required to keep on track, and less dartyness in the steering overall, but this could just be mind games and I need more miles before I can actually definitively state this. I cut down the steering tube to lower the handlebars of the S40 at the same time, so separating the results will likely be difficult.
I also want to see what impact the headset will have on the S40 when I resume pedaling on a downhill. My pedal stroke was rough enough when I started on the S40 that I had to allow speed to bleed down below 20 MPH before I could resume pedaling without risking wobbling out of control. Before cold weather set in last year, I had improved to over 30MPH, but it was still too wobbly for my taste.