I won’t tell you how many loops I can handle without side-effects since it would just confuse people and serve no constructive purpose. Suffice it to say I can take a beating.
One factor which makes a difference is definitely the food I eat. When I eat a healthy primarily plant based diet I feel very light and airy in my head, like I’m breezing through the subs. In full-scale ketosis, it’s harder (possibly because I’m not fully metabolically flexible yet) and I’m yawning all over the place because energy is just not delivered fast enough. A meat-based diet or fried foods divert so much effort to my digestion that I become unable to have creative ideas or do complex thinking. In both latter cases I can recover much faster if I turn off the subs.
Another factor might be because my mind is very good at simply turning off the receiver. This might explain why I need many more loops or a different approach. I wouldn’t call it stonewalling, instead of resisting, my mind simply ignores it.
And finally, my brain does everything on overdrive. I often do two or three things at the same time to avoid my mind wandering off. I also speedread when I can, can listen to audiobooks up to 10x speed if I do nothing else as well as watch TV at 2.5x speed. So maybe there is some wiring there which can handle lots of subliminal input. But there’s too many downsides to recommend it.
Something which is very important to consider is that the recommendations exist for a reason. Yes, a part of it is because lots of people get adverse effects when listening too long. But there is also research done which indicates that even when we don’t feel anything there is still something going on and like training muscles, it is the resting periods during which the subs do their magic (might this explain delayed tiredness?).
Hence, even I start by following the recommendation and very slowly change things. I may make one change every week and then observe what it feels like the entire week. Or a more recent thing is that I may spontaneously choose to throw in a rest day. I see it as no longer putting the pressure on myself to process as much subliminal as possible in as little time as possible. Instead, I simply assume there’s always something going on. And if there’s not, then I’m still taking action.
Following the recommended number of loops, you could listen in the morning one day, in the evening another, before food or after food. Instead of experimenting with exposure time, experiment with all the environmental factors. I find the effects of when I listen, what I eat and what I think to be far more noticeable than increasing or decreasing exposure.
He also showed compassion when he saved Katniss and Peeta, even if he didn’t really have a choice. 
As far as I know, ZP was balanced out because of the effects it had on the testers. It was with good reason. And it may even have simply been decreased in duration without decreasing its power, so that a wider audience can use it while others can do an extra loop.
Did Saint say otherwise? He did say “this is why you can’t have nice things” but that was more him being disappointed, not changing his plans. As far as I know anyway.