So for 1 gram of gold, you need (minimum) 174/196 grams of sodium chloride.
You also need 1.5/0.03 ml of 3% peroxide (about 50ml). In practice you will need more.
I'm going to give this a try soon, I'll be using 35% food grade peroxide though. I will try working with 100mg of gold leaf to start out, cutting the portions you shared by 1/10. Does this process look okay:
Add enough distilled water to 89 mg (174/196/10) of sodium chloride to create a saturated salt solution, leaving a little excess salt in the bottom to be dissolved when the solution is heated.
Heat the salt solution to a simmer, add my gold leaf and then slowing add 35% a few drops at a time, just enough to keep the reaction going.
Check on it periodically, adding more peroxide as needed to fully dissolve the gold leaf.
If this doesn't work out as planned, I've been thinking about using bleach + peroxide. Do you think household bleach would be safe to use for creating colloidal gold? If not, what about creating gold chloride via electrolysis instead of colloidal gold directly? Reason being that the colloid created from AuCl seems to be more stable.