I'm around 800-900 light and all I've done is a few Syrcus Tower a week, the occasional expert roulette, and Frontline. I don't feel like I'm grinding Nexus; I'm just doing my normal thing with my Novus equipped knowing I'll get a Nexus eventually. I may push things if the next upgrade stage is close so I can start it right away but an i110 weapon is fine for me right now.