10-12,000,000 seems like a good baseline for an hour speed-up with a **chance** to get more. The truly hardcore could probably convert that into 6-8 hours a day and even the semi-casuals could easily get 2. Nexon would never go for us shaving 6 or 12 hours a pop for less than one training blessing worth of looting, maybe with the pre-museum economy, but certainly not now.
My gold was maxed earlier today. I started an anti-aircraft gun upgrade for 6,000,000 gold. Now about 4 hours, 4 raids and collecting from my caravans later I'm full again
Gold is far too trivial in late game to reasonably expect much more than an hour baseline with a slight chance at something more, methinks. That said, the baseline has to be high enough to where people don't just easily cash out every night before logging off and stagnate the economy. This is much more relevant to food than gold though. I don't foresee a need to implement an oil version of this. If you're literally swimming in oil then you've probably reached Peak Dominations and don't need much in the way of incentives at that point. Would love to hear from some of those folks though.