Well, if you want to avoid long hauls you could try this:
Nested immediate turnarounds to ZRH, there's a Swiss J offer to HEL going on atm. Return in Value. This would net you 15000 points, the award points which you could then convert to the last 5k points you need making it point neutral basically. Total price apprx. 734€ (The J flights need to be booked on an OTA, I used
CheapTickets to price this one.) Finnair's site bumps up the price.
You could probably get sufficient points with a long haul, but I think with accommodation costs it could get higher. Depends if you want a mini holiday or just points.
