120 should be the upper limit for a number of reasons. Sure, our CAP can have enough bulk to take resisted hits, and neutral hits from weaker pokemon even, but too high a PT would prompt people to invest in their Defense, and so we create a CAP which is effectively a wall which has the potential to be overpowered, especially when taking into consideration its attack stat. This is obviously something we don't want. The best PT we can get with 120 as a limit is 111/62,(119.6307) which is a good amount (maybe too much :/) to not be taken down by certain physical moves which this CAP can resist, whilst also making the user invest in other stats which would be more important/useful. An argument was brought up in #cap about not needing too high a PT because there's literally nothing physical we should be wary of, bar a possible Choice Band Earthquake from a pokemon such as Garchomp. Below Average and Above Average should be the area we're aiming for with our PT.
Now, I'd rather a lower SS than 75, but we need to take into consideration fast spreads. 111 Speed, which has been mentioned a couple of times for outspeeding Lati@s, means that a Special Defense of 35 is still above 70. Now, this brings me onto the next point about abusing stat limits. We don't want speed of less than 40, there's no precedence of that in OU, and it shows a sign of manipulating the stats too much in order to get what we want, and potentially overpower this mon. If we're going with a fast stat spread, which I'm opposed to, but if we are, than an 80 upper limit would allow 41/111.
This can depend on the speed stat of your spread. A slow speed would allow more room for needed special bulk, whilst a fast speed would need less physical bulk, as you're moving first, and so can use potential moves such as Rapid Spin or Wish with ease, whilst not taking another turn of damage. The highest special bulk you could have without passing 245 would be 92/151, which is still very high but would be expected on a slower spread. Regarding the suggestion of having Excellent ST, I feel that would be too low to substantially counter Lati@s and Politoed, amongst others. Don't forget that Latios has 242 SS. For our spreads, I'd expect a high Fantastic or a low Amazing.
Again, this depends a lot on speed. If we're going for a fast speed, than only a 78 or 79 attack is needed. If we're going slow, it allows more room for a larger attack, somewhere in the region of 85-105. We need to be able to hit Lati@s hard, Politoed included, but there certainly shouldn't be any OHKOs, that could be too powerful.
Now, my main concern is Lower Limits. Speed is the main reason why I am opposed to Lower Limits; it affects the SS and PS hugely, and if we were to go ahead with Lower Limits, that would discount many viable spreads due to their dwindling speed. For example, if 90 is the agreed Lower Limit of PS, than a base 30 speed mon needs 123 atk, meaning that it could potentially become a bulky sweeper, or just way too overpowered. An abscence of Lower Limits has worked fine for previous CAPs (excluding Krilowatt), and I don't see the need to change it now. If it gives you the freedom to abuse the stats, than so be it; your spread won't get slated.