I've looked at some saves people have provided and at building costs, and have come up with an approximate formula for what a good hammer cost for buildings would be. This is from mid-Classical to the end of the Transhuman,
so excludes the Prehistoric and Ancient eras
The X is the X column of whatever tech enables that building. That would lead to the following
- Cost of 125 hammers at the start of the Medieval Era
- Cost of 300 hammers at the start of the Renaissance
- Cost of 650 hammers at the start of the Industrial Era
- Cost of 1650 Hammers at the start of the Modern Era
- Cost of 3000 Hammers at the start of the Transhuman Era
- Cost of 9500 Hammers at the end of the Transhuman Era
This is the cost in the XML, that will be larger ingame due to gamespeed modifiers. This would be for buildings. For other things, here are what my calculations say would be good.
- Units: Same as buildings. Units will be cheaper because the multiplier for their costs in the gamespeeds is about half.
- National Wonders: 4x building cost for appropriate tech
- World Wonders: 10x building cost for appropriate tech
- Projects: 12x building cost for appropriate tech
How does this sound?