(cwl)
About atropine, no idea about the price my friend. Never tried it, and to me if PGE-1 works well, I wouldn't try something else.
About tolerance, I have heard about it, but at least in my case I never experienced tolerance buildup.
However, there is an old chemical PE guy that used to be very popular around blogs back in the day, his name was Ronielle, a canadian gay escort, who was experiencing all kind of chemicals on his penis. He had some gains, I believe caused by sheer volumetrically pressure, but he was using insane doses. According to him, tolerance buildup. He was injecting up to 250mcg of PGE-1!!!! That is INSANE. Imagine if an average male can get an hour erection with 2.5-5mcg, imagine injecting 250mcg!!! He was also injecting a lot of other chemicals in a cocktail and could barely achieve an erection of 40 minutes at 90%.
Eventually I believe all this caught up with him and had to stop in order to attempt to regain some function. I always criticized his approach. I always keep it on the safe side. If I see for example that 1mcg doesnt do anything for me anymore, instead of keep jacking up the dose, I stop it. To allow my receptors to re-sensitize over time. Sure, I wont be able to play with it, but health first.