Love the countertops. Never been a fan of sinks that sit on top of countertops because I just envision the edges where the counter/sinks join as a cleaning problem (not that I clean them) so I'm curious to hear, 6 months from now, that I am wrong.
It's fine the same as the joint between the back splash and the countertop. Tape both planes very close to the joint, and run premium clear silicone along the joint.