The more effective ways to large gains include shop multipliers and gains week CEO items. CEO items will also increase your daily key cap, letting you gain more rubies per day, letting you increase shop multiplier faster. CEO items give the most immediate boost that I could see, so try to get as many of those as you can during gains week.

I'm "only" at lv347 and I can max the weekly tournament rewards in 5 minutes. I have all CEO items and shop multiplier currently at lv27. My increase from resetting isn't worth the time and effort, I just do the 5 resets weekly for the daily quest.