CH access for FC Gold when flying on Delta metal?

Greetings, all.
I'm an FC Gold member flying on VS 4036, the DL-operated LHR-SEA service (which departs from LHR T4).
Does my FC Gold status entitle me to use the CH in T3 when traveling on an Economy Comfort ticket, issued as a VS codeshare on DL metal? I ask because I imagine the CH is much nicer than any lounge DL offers in T4.
(I realize this would mean needing to get from the CH in T3 to T4 before the flight. Does it also mean needing to check in at T4 before going to the CH in T3? Or will VS happily check me in for the SEA flight in T3?)
Thanks very much,
Brad
I'm an FC Gold member flying on VS 4036, the DL-operated LHR-SEA service (which departs from LHR T4).
Does my FC Gold status entitle me to use the CH in T3 when traveling on an Economy Comfort ticket, issued as a VS codeshare on DL metal? I ask because I imagine the CH is much nicer than any lounge DL offers in T4.
(I realize this would mean needing to get from the CH in T3 to T4 before the flight. Does it also mean needing to check in at T4 before going to the CH in T3? Or will VS happily check me in for the SEA flight in T3?)
Thanks very much,
Brad