Sorry. Nothing to disagree about. The vomiting just isn’t part of its general consumption as a tea.
By the way you posted a link which literally backs up my statement. 
Edit:
Perhaps I shouldn’t have said “copious amounts” as that implies a large volume of tea. Your reference indicates that it would be a very concentrated tea (mixed with additional herbs) meaning the large amounts are consumed without the actual volume of the tea being so large.
If you grow some Yaupon From what I read is you should cut the branch, and hang it upside down for 2 weeks this makes the Caffeine break down so when you prepare it your body Absorbs in in the finished tea.
If you’d like I can get the Link later?
it is a short read of how to best extract it (busy now though)
(the hybrid you speak of with ilex glabra ,and Yaupon
ilex glabra is Called Appalachian tea
(but a common scientific name glabra means grows in bog )
That hybrid is for cold hardiness I know (or believe ) , but keep in mind also good for wet soils.
No it doesn’t the plant contains caffiene
More likely the Berries would cause Nausea , not to much Caffine
This is what I first expected , but decided to not post (and save statement in email.)
Also even a Modern Herbal Doesn’t think the tea in large amounts would cause it
Vomiting can be a side affect of caffeine overdose.
However, I never made any claims that the caffeine content of Ilex vomitoria was the culprit. I only asserted that one need NOT be concerned when consuming it as a normal tea. The association between this species and vomiting is NOT related to simply consuming it as a beverage. The fact remains that the vomiting is associated with concentrated preparations combined with certain ritual practices. I’m not sure how I could be more clear.
I think If you do the south side of a building thing, and grow some dwarf varieties, you could probably protect them. I have a "Will Fleming " from woodlanders that grows straight and narrow, almost corkscrew like. That one might do well since it would go up under an awning.
The tea is actually quite good with some mint simple syrup and lemon…
I did not mean it in that way that I doubt people may have used it as a emetic (to vomit)
What I did decide not to post was Even bitter tea will make you puke
The tannins can I know I love Bitter black tea
Yuapon or illex tea I’ve drank do not seem to be bitter, but I am sure it could be concentrated
My point was that the person that named it may have had a agenda not to lose Market share of regular real tea , by naming the latrin name vomitica tea since he had associates with the British Tea company
even a other famous botanist tried to have him change the name.
By the way
In South America it is a popular drink (Yerba Mate)
When In Miami I went to Little Havana you can get a huge bag for cheap
(If there in Miami could get good deals)
original poster
I also have some in tea bags
you may want to try regular verse roasted on fire (as has a wood smoke flavor )
(if you want I can give brands name)
This will give you a idea of what you like before processing
(I never had Gunpowder tea yet,
but maybe I can develop a taste of this smoky taste over time of drinking it
what I have reminds me of gunpowder tea’s description at least.)
some interesting places to buy from here as well as interesting article
I also have some Native American archaeology stuff (link) this tea was actually found to be traded in IL. as well.
https://www.herbalgram.org/resources/herbalgram/issues/109/table-of-contents/hg109-feat-yaupon/
Some people may not like it because of the name
This would not be the first time I’ve heard bad stuff of a food (hawthorn tejocote )
but sometimes you got to ask why is such a food revered in other cultures, but not by Americans ?
(I will admit we all make mistakes
I re cooked a gift of with Masa (corn / food) the wrong temperature , and it was bad tasting
but now I learned, by trial , and error , and love their culinary gifts I received )