To be honest, for 50.000 NOK per booking you should get a gold plated seat, I'd say. Yes, it's fast, but it's a bad deal. For 100.000 NOK I can probably get half a million points with smart booking and normal flying behavior (and a bit of luck).

If you want to get gold on the cheap I'd rather recommend to wait for SK to have long haul to SFO or PVG on the cheap and try to get some OT upgrades: you should get 10.000+ points per flight and it shouldn't set you back more than 3000NOK for the booking and 1000NOK per leg for the OT upgrade. Also, make sure you have some feeder flights into CPH. You can book some cheap plus fares from most cities nowadays (just make sure it's outside the Nordics for better points). In total, it shouldn't set you back more than 15.000 NOK and 8 flights to get from Gold to Diamond this way. Only weak point in the plan: there's no guarantee that you'll get the upgrade via OT...

I thought SK made the fast track to Gold last year to promote the new 'Plus' concept. I do hope they will do something like it again this year, but I think chances are slim (also because the SVG-IAH route is new and now being promoted this way).