Assuming you explore 100% in 3 bg, then a loss will score more than a 2 BG win, that will be approximately 510k points vs 442k points. The problem is you will not stay at tier 6 forever. Keep losing and you drop in tier with a lower multipliers. If you can win some wars with 3 bg, that would be the way to go for more points imo. But if you can’t fill all 3 bg, then I would rather go with 2 full bg instead.