The original Tea Hong direction has been written aiming at general users who normally use a tea mug or tea pot for making tea. Basically the original idea of adjusting tea to water ratio means using more or less leaves, or a larger or smaller infusion vessel.
Tea infusion is a management of not only the water temperature, tea to water ratio, but also the heat behaviour within the infusion vessel; therefore the size, material, shape, and timing and manner of how water come into contact with tealeaves. The physical and chemical nature of the tealeaves also play key roles.
Having said all these, basically, it seems to me that a 100 ml gaiwan is setting you up for the way to do it only in the gongfu way. Chawang is right. Smaller and thinner vessels facilitate short infusion approaches and not so good for longer ones. To do it the conventional way, you have to use a larger vessel. A larger vessel means relatively slower heat loss to enable you to control the other variables. A smaller one holds the total heat relatively shorter. It is a matter of physics: total surface area to volume.
Generally, a 250 ml vessel with thick material, holding 2.5g tealeaves for 2~3 minutes should give you good result. If you use a 100 ml gaiwan, try DOUBLE the tealeaves but a quarter or one-fifth of the duration 
Amazing fun, isn’t it?
Amazing fun, isn’t it? I’ll talk a lot more about the variables of infusion in later TG articles.
