This is a complicated question to which the most meaningful answer is: go train jiujitsu.
I'm not being flippant; there are so many paths to follow, dependent not just upon the size and strength of your opponent but even more so on his own actions... jiujitsu is an ocean of options, deep and wide, in which you'll feel like you're drowning when you first start training... eventually, you'll have a response, a choice of action, from almost every position.
To answer your question in the spirit in which it was asked: I would seldom attempt a throw or takedown against a larger guy, unless his posture and movement make me very confident that he has very little skill in takedown defense... I'd wait for his takedown attempt, and use it to (a) take his back, preferably, or (b) end up in side mount.
But that's not because those are better, it's because that's the game I've developed as my grappling has evolved through training.
(In reply to this)
Thanks that's interesting. But it seems to imply that submission wrestling depends on bjj. Maybe that is the case but surely wrestling has its own technical array?
There are not that many traditions of submission wrestling, at least not many which are adequately popular, which a person could go find training in: jiujitsu, sambo, judo... that's pretty much it. And, all these styles have many points of overlap, because there are only so many positions two humans will end up in while they're trying to bodily control each other.
Also, the growth of mma has created a great deal of borrowing; traditional Brazilian jiujitsu (though the art is so young, "traditional" almost doesn't mean anything) is light on takedowns, but any decent jiujitsu school you go to will be teaching you the takedowns originated in wrestling which finish in positions conducive to working towards a submission.
So, the simplest way to access the skills you're seeking is: go train jiujitsu. :-)
Well thanks for your comments. I will certainly consider them.
How is your shot? If you don't have a good shot, you will have a very high failure rate of aggressive takedowns against a bigger guy; a single leg would be good but you'll need to win the scramble to side mount, or end up in half guard (possibly bottom half, if he's strong enough).
If you don't have an excellent shot, I'd wait for his takedown attempt and use it to go for his back or run your own takedown.
I don't know any effective way to describe in words what I'm talking about: this is why I usually end up back at "you should go train."
Good luck, bro! 👊
This is a straightforward question directed to submission wrestlers here (as opposed to pro, boxing, kickboxing and heel/jobber)
What techniques to other sub wrestlers successfully use when wrestling bigger opponents, by which I mean an opponent who is significantly taller and/or heavier? If you go in low from a standing start, for example, how do you avoid being forced into defence? How do you work around having a shorter reach?