It's been stated in other threads, that the weave pattern is actually safer than the star. It yields less points, due to the fact that you don't take the left side hammer...but instead weave to the top and then grab the middle hammer immeditely.
The weave often lets you get to the middle hammer without any trouble from firefoxes...but sometimes you get trapped in the same manner that you get trapped in star pattern attempts.
My best tip for rivets is to not be scared of the firefoxes. Elaborating, whether or not Jumpman's actions have any sort of influence on firefox movements...I always will run in the direction of my objective...towards a hammer, towards a rivet...until I have to turn back. Reason being, if you expect cooperation from the firefoxes...meaning assume they will run away from you if you are running towards them to grab a hammer or whatever...it puts you in a better position for when they 'do' cooperate...since you'll already be 'on your way' to going wherever you wanted to go.
It's one of those coincidental/accidental/random things in this game that seem to work out if you believe in them...if that makes any sense. For example, I'll go out on a limb and admit that I sort of believe you can steer firefoxes down ladders just like barrels can be steered. It's much less of a % chance, but sometimes it feels like you can do that.
Same thing with running at a firefox...its almost like sometimes they don't want to kill you (have you ever point pressed the 1-1 fireball that comes out of the oil can, only for it to turn around and run away from you over and over every time you are trying to jump away from it, resulting in 0 points because the hit detection is off since it is running away from you)...and if you run at them they will turn around and run the other way...sometimes this makes the difference between being able to get to the middle hammer from the left hand side during the weave pattern...or sitting there waiting for them to run away themselves...only for your timer to get to low...creating a panic situation where you have to jump firefoxes...which normally results in death.
Run toward your objective until you must retreat...even if it means jumping over a rivet hole to the middle section of girders where 2-3 firefoxes are running around...you might be surprised when they all run away and let you grab that middle hammer...and even if they don't, you're that much closer to the hammer...just in case they do run away 2 seconds later.
--To better answer your original question, the first 5-10 seconds are key in making a decision as to how you might want to approach a rivet stage. Aside from the obvious star or weave patterns, if firefoxes all spawn toward the top and run left, its often best to freeroll...take out the bottom rivets on both sides first...until a couple firefoxes get lured down...then go for the upper rivets. Try to box out as many firefoxes as you can while freerolling...keeping them to the left and right sides if you're in the middle...on in the middle/left sections if you're on the right side, etc. Being patient, and letting firefoxes come down as far as possible...and as many as possible...is key. You must balance being patient with your bonus timer clock left, though. There comes a point where you simply have to go for it. Good example of this is Ross' Wildcard Rematch 21-6 run.
