You never want to produce Wealth even at 50% of Hammers. The Hammer:Gold conversion ratio is 4:1 or worse for anything except unit upgrades, and even then it doesn't begin to approach 1:2.
Well the idea is How you go about making gold
There are a number of ways, and different ones Should be more or less effective
1. Build a Farm on a tile to increase population to increase trade route output.*(gives other benefits and costs)
2. Build a Farm on a tile and run a Merchant (gives other costs, few other benefits... limited by buildings)
3. Build a Lumbermill/Mine and build Wealth (requires tech)
4. Build a Lumbermill/Mine and build/Disband units
5. Build a Trade post
The order from Most to least effecieint SHOULD BE
Trading post > Wealth > Build/Disband units
Merchant Specialist could be anywhere from Trading post to Wealth
Trade Route could be anywhere below/ equal to Wealth
You Don't want Hammers->Gold->Building to be better than Hammer->Building
But more importantly, you don't want
Hammers->Gold
to be as good as
Gold
so 100% would be too high (Lumbermills would be better than trade posts.)
and 50% is a good round number
and it means 8-10 hammers here=1 hammer wherever you want.