Excellent write up Court and this saved my day, thank you.
I just bought a 98 VFR which had been sitting for 10 years so you could imagine what the brakes were like. The SMC was totally seized as were some of the caliper pistons but was able to pull the piston out with a drilled hole and a self tapper screwed in. Ended up rebuilding the calipers, clearing the SMC port and removing the ball and spring from the green filter and now its all good. I just have to finish sorting the wiring as rats had made a nest in the v and chewed wires and hoses they apparently thought were in the way.
I did have a similar problem with my Blackbird some years ago but after caliper rebuilds and MUCH cleaning it was sorted. Of course I didn't understand the green valve and SMC at that point but must have cleaned it enough to sort it. In fact I just went out and bled the Blackbird brakes after the VFR exercise to hopefully prevent it happening again.