OK, last game was Huge, all planet options to normal mid-point setting, all victories enabled, max races, suicidal difficulty (doesn't show up in meta submission
Custom race - 5 pts into Diplomacy (of course
), 3 pts PQ, 2 pts Research. Populist party for more Diplo bonus.
Lesson learned - turn off Cultural victory, happens too fast!
Looking at the scores of other players, it doesn't look as though the diff level has much effect on the score, and tech whoring is the way to go...