I think the best answer to this would be I would "expect" you guys to fly whatever speed you need to for profile (how's that for a non-committal answer
) . Speed certainly is can be black magic, and I do find it amusing sometimes that same types of aircraft are being flown at drastically different speeds. Yesterday afternoon I had two CRJ 100s filed the same route, same IAS, same cruising altitude but different company. The second guy was doing his best to try and smoke the first (of course, I don't know who was carrying more of Winnipeg's world famous ah, err, ahhh ........forget it)
If we need you to fly a specific speed for sequencing or separation, we'll let you know. Especially if you're asked "GLF!"