Well, I'm under the assumption this is a relatively safe experiment so I figured safety glasses and rubber gloves would suffice.
As well as plenty of open space... was planning on doing this indoors (I have about 20' of ceiling height where I am doing it). If you think that is insufficient then I could just as well move it outside.
It is my understanding that the reaction is hot and can be a skin irritant but can be easily cleaned up with water.
I like your safety thoughts.
It appears to be safe for the inside, but outside might be better.
At least for the first time.
I saw 1 video where the stuff hit the ceiling an that would make for a messy cleanup.
The Hydrogen peroxide does have a bleaching action so a lab coat may protect your clothing.
I was wondering if the reaction being exothermic (producing heat) would be too hot for plastic,
but I see some web sites using plastic bottles.
In any case, I would have the container on a level surface and not holding it in your hand.
When you do the experiment keep in mind heat is created.
This is supposed to be relatively safe experiment,
but when they do it with kids they use different reagents which are safer.
I would say that you would not want to use the whole gallon of hydrogen peroxide.
Start small and build up is usually a safe plan.
I will be away until tomorrow.
That should give you enough time to think about those dissolve solution question I asked.
Also you might read more pages on the internet
GOOGLE elephant toothpaste
When I do an experiment - I do reading research first.
I do not necessarily try to read everything.
But, youtube watching should not be the only source.
I see you said you read some sites but you might look up the kids version of this experiment.
I have not done this experiment myself ----- yet
but you got me thinking I should have
By the wayhttps://www.translatorscafe.com/unit-converter/en/concentration-solution/3-13/milligram%2Fliter-gram%2F100mL/
EDIT: the below link is better see my later apology post
mg/mL to g/100 mLhttp://www.endmemo.com/sconvert/mg_mlg_dl.php