Some thoughts/questions about Primer

I've been revisiting Primer a bit recently.

I find Shane's decisions around the story really, really bizarre. The first two acts of discovery/testing are amazing - very detailed, well thought-out, atmospheric with its sense of wonder and excitement. The first hour is just terrific.

Once this set-up is established, the situation is so ripe with vast options available. Will they get crazy rich? Will they try and correct some huge international news crisis before it happens? What if something like 9/11 happened while the failsafe was switched on - could they realistically do anything about it? Will they go insane with the sense of power/responsibility?

No. What's the first thing that they're willing to risk the grandfather paradox on, putting themselves through the "there's no way this is remotely safe" process? Stopping a kid from hitting cars with a newspaper so Aaron can sleep better. I mean seriously, wtf? Then Aaron admits he abused the machine without Abe's knowing in relation to a guy showing up to a party with a shotgun - which they then become obsessed with, implying endless loops to "perfect" making sure the guy gets arrested - even though Abe admits he never fires the gun, in any permutation. Again, wtf? Is it really worth risking this unsafe process, which is damaging their handwriting and making Aaron bleed out the ears, just to stop a not very nice thing happening that actually affects noone? What then, are they going to Timecop any unsociable act? Gosh Abe, I'm on my way to the storage facility, I just saw someone steal a car parking space at the supermarket.

Then using the failsafe, and Abes trauma at knocking himself out, to prevent Thomas Grainger ever using the machine. How exactly? What if its his reaction to this event and use of the failsafe that somehow leads to Grainger using the machine? Why doesn't he destroy the machines at that point, to prevent Grainger from ever being able to use it? If there's no machine, then Grainer can't possibly get into it, so his presence in their timeline would surely disappear?

Also, when they first use the machines, why don't they just switch them on, open them to pull out a letter from themselves with stock information, close it again, then invest in their stocks from the letter, then write the letter and post it to the box at the end of the day? They don't once consider the concept of posting information backwards rather than themselves.

Also, when Abe uses the failsafe and faints while talking to Aaron at the bench, was it seriously his plan to repeat the days events to ensure that Abe and him went back again? And how did he survive three days shitting/pissing in that tiny box?

And why does Abe talk about stealing "their" passports, as if they are clones of the real people now, rather than themselves? If they're able to permanently replicate themselves by not treating time as a block event, (like Tenet), then why not just keep posting money back and doubling it, replicating millions of banknotes and hoping no one notices the duplicate serial numbers.