IDK, I've rolled with some pretty big guys not saying my arm triangle technique is perfect but when you roll with a guy that is 220 with massive shoulders whether your technique is perfect or not I think its very hard to do and will waste alot of muscle energy , no one just lets your cross the arm over people will post their hand on their face ,elbow to your head and not let that arm go across so then it comes to a squeezing game
EDIT: after a while people will get good at defending guillotines and RNC if you keep getting them but thats part of the game , theres a reason marcello can hit it on anyone he didn't give up on it when people started defending it well and found away around their defences making him better and better at it
Like I said, you can't just force the arm across on someone strong, you have to kill the arm in an intelligent manner, i.e. encourage him to put it out of position for you, either in a positional transition, or as he uses it to push to defend against something else you are doing. You then only have to give the arm a little nudge as you drop into position and tighten everything up so he can't make space again. There are also ways of simply using superior leverage to force the arm into position, but against real beasts, I think the former strategy is the easiest. If he manages to 'answer the phone' once you are in a decent finishing position with most of the space killed, you probably have the leverage to choke right through his defense if your pressure goes into his shoulder (if you put your pressure into his triceps, like 99 % of BJJ players do with the arm triangle, his defense will work). If that somehow doesn't cut it, there are also numerous ways to peel his hand away from his face.
Now, if you do come across a guy who is so big and strong that he is able to maintain posture and negate your arm triangle pressure, his defense still opens up his neck for your RNC, guillotine and North-South choke, a reaction you may not have gotten otherwise. Not every attack in your arsenal has to be with the intent of finishing; sometimes a predictable reaction is almost just as valuable.
In any event, though, I don't believe that a proper arm triangle should ever turn into a 'squeezing game'; you should only be squeezing to eliminate the last remnant of space within the choke, while you use your weight and position (or the shoulder-drop if doing a 'blade' choke like the brabo or Ezekiel) to exert the pressure. Yes, you will probably squeeze as hard as you can when going for the finish in an actual fight or tournament, but that's just icing on the cake, and should only be to speed up the tap.
As for what you say about Marcelo not giving up on the RNC or guillotine and finding ways around the opponents' defense, I don't see why the same can't apply to arm triangles. Just as Marcelo has found the right leverage and right timing to get under a big, strong opponent's chin, an arm triangle expert can find the right leverage and timing to get a big, strong opponent's arm out of position. I'm sure Milton Vieira taps big guys all the time in training with arm triangles.
Now, Marcelo may not have the ideal
build for becoming an arm triangle specialist, as he has very short arms (though this is not a problem with all arm triangles), but that doesn't mean that his dismissal of arm triangles as some kind of strength move is entirely accurate. Don't get me wrong, I listen attentively when Marcelo speaks on grappling, but he tends to categorically dismiss a lot of moves that others are currently winning world championships with (arm triangles, DLR guard etc.), and I think this is more his way of staying focused on the techniques he really believes in, than an actual rejection of these other moves' validity.
