The only thing I have to add is that if your research with videos is porn, don't judge anything by that. Men are often doing a number of scenes each day, so their erections won't be the same as yours, nor will anything else. It's also not nearly as sexy as it might seem to act out sex with a dozen people in the room with lighting and sound equipment, etc., etc.
Nothing about porn is a guide for reality.
P.S. In my opinion, there are more possible reasons than mere arousal for the amount of precum and ejaculate to vary from time to time in any one individual and from individual to individual. Obviously there's the length of time between occasions, between ejaculates, i.e., how long the body has to replenish the supplies. Then I would suggest further the state of one's mood and physical vigor on any particular occasion (e.g., tired, low energy, too little sleep; rested, refreshed, full of energy); immediately previous diet, quantity and type of liquids imbibed; length of anticipation and stimulation; and doubtless other such possibilities that could come to mind. But above all, it must surely be like all other human traits: natural physical variations from one human body to another. Norms are only that: norms...figures derived from a multitude of variations. So if you produce copious amounts of both fluids every time, don't worry---be happy. Consider yourself fortunate, enviably blessed by genes and nature...!!!
Are you not exaggerating when you say your precum covers your entire "penis and crotch area" That does sound a bit unusual, but as Paxiled states, it is quite normal for the amount of precum to vary from man to man...and depending upon the degree of an individual's arousal. Yours does not sound to me to be anything to worry about, but if you are uneasy, for your peace of mind you could have a urologist check you out and give an opinion. But as Pax also suggests, plentiful precum and ejaculate are considered by most men to be highly desirable...and enviable! Precum is nature's own lubricating, pH-adjusting fluid, facilitating smooth, painless penetration and intercourse---especially helpful if the woman's natural lubrication is less copious. As for the amount of semen ejaculated, it seems to be a truism that most men seem to get more bang for the buck the larger the amount: the more the merrier, as it were. ~~~ P.S. If you do get a urologist's opinion, please let us know the outcome.
Not exactly sure where your problem is. All erections are rigid and throbbing -- pretty much the definition of an erection. As to the amount of ejaculate, that depends on how turned on you get. It also can depend on how long you can last before ejaculation -- the longer you hold it in the more ejaculate and the more powerful the orgasm. The power of the orgasm depends on how turned on you get. If you're getting very turned on, you'll ejaculate more. If you ejaculate several times in a day, you'll release less and less quantity, as it takes time for the body to manufacture more. As you get older, stuff happens, and when you get old, lots of stuff happens, and that also affects all of this. What's normal is different for different people, as different people have vastly different levels of enjoyment of sex, sensuality, etc., all of which affects the quantity you expel.