If you're metro-HEL based, I'd suggest to arrive as late as you can (or dare) - nothing worthwhile to do waiting for your flight. Shopping? Not much sense outbound. Lounge? Well, that's what this whole thread is about. If you're connecting in HEL, that's another story, you don't have much choice for timing. For HEL-FUK at 16:45 I'd arrive not earlier than 15:30. With your AYGold you can use the fast track security upstairs, the automatic passport gates are hardly ever congested and you'd still have time to witness the current state of affairs at the AY Business lounge.