My mom is from Brasil and I remember she would always prepare mate in the gourd growing up - she served it with sugar and milk. I have both
this tea in bags and the
loose tea and will say they don't taste anything like eachother - you need the loose tea to get the authentic taste. I don't have a gourd either so I make it one of two ways - in a tea pot/press that has a strainer in it or pour some into a coffee filter, seal the top with a rubber band (washed) and throw it into a big pot of boiling water. If you want the gourd and spoon - you can get them on Amazon.
As far as the caffeine effect - I'm very sensitive to caffeine and did notice a reaction to it when I drank almost a whole pot of tea (funny tummy) but didn't get the extreme high blood pressure and racing heart that I do with some other teas I've tried.
From Wikipedia:
Comparison of effects with coffee
Mate's negative effects are anecdotally claimed to be of a lesser degree than those of coffee, though no explanation for this is offered or even credibly postulated, except for its potential as a placebo effect. Some users report that drinking yerba mate does not prevent them from being able to fall asleep, as is often the case with some more common stimulating beverages, while still enhancing their energy and ability to remain awake at will.
However, the net amount of caffeine in one preparation of yerba mate is typically quite high, in large part because the repeated filling of the mate with hot water is able to extract the xanthines very effectively. It is for this reason that one mate may be shared among several people and yet produce the desired stimulating effect in all of them.
From reports of personal experience with mate, its physiological effects are similar to (yet distinct from) more widespread caffeinated beverages like coffee, tea, or guarana drinks. Some users report a mental state of wakefulness, focus and alertness reminiscent of most stimulants, but often remark on mate's unique lack of the negative effects typically created by other such compounds, such as anxiety, "jitteriness", and heart palpitations.