Ok, so I just got finished reading the whole story. Here are the feats:
Obviously after getting his amp we see him lift 200 Quintillion tons, noted as being 3x his natural non amped record:
https://2.bp.blogspot.com/-Nu7o5wKHf34/VjnB6EjxSzI/AAAAAAAAC2s/Wz2nW66ndxA/s1600-Ic42/014.jpg
With it being noted that this wasn't even the upper limit of his new found strength.
200 Quintillion tons is, what, a 3rd of the Earths weight? I'd say that's a good enough case for a Class Z rating and possible moon level striking force, tho that's up for debate.
With all this in mind, his non amped lifting strength should have been at about 66,666,667,000,000,000,000 Tons.
The other notable lifting strength is that 500,000 ton key to his fortress, which as shown by Bar El and Lilo even a non amped Superman could casually lift such weight:
https://2.bp.blogspot.com/-ujOAZGZOu30/VjnHIr2AueI/AAAAAAAADQY/AroKfssrmLE/s1600-Ic42/008.jpg
One thing I want to note as well is that its made clear that Superman is the only person on Earth capable of lifting the key:
https://2.bp.blogspot.com/-A3geza_cYsQ/VjnCbPhOuPI/AAAAAAAAC50/RwI_NgZlXPI/s1600-Ic42/005.jpg
Which would mean that any powerhouse type hero or villain's strength is at least just below this range
The only other heroes mentioned througout the comic was Batman, Wonder Woman, Flash and Green Lantern:
https://2.bp.blogspot.com/--ptR5nC6YBw/VjnGieboqwI/AAAAAAAADNM/mIcOB0UB47g/s1600-Ic42/013.jpg
One last thing I'd like to mention before moving on, its noted that All Star Krypton's gravity is only 8x greater than Earth's, where its mentioned as being 30x greater in the main continuity:
https://2.bp.blogspot.com/-NHcOODFlgz0/VjnHv9S-aEI/AAAAAAAADTs/TzR-yOcGvXQ/s1600-Ic42/006.jpg
This doesn't necessarily mean anything other than a downgrade for non-ampd Kryptonians, just thought I'd bring it up.
Here he states he picked a flower from Alpha Centauri:
https://2.bp.blogspot.com/-GLikxTXjDe0/VjnCbUUH4xI/AAAAAAAAC50/HxA3zRha71c/s1600-Ic42/007.jpg
Light takes roughly 4 years to reach Alpha Centauri and I doubt he took that long on such journey's. Its not clear as to whether this was done Pre or Post Amp but either way its a solid speed feat for him. I'll let you all decide the High and Low end for this one as no time frame was given.
How much do any of you think these miniature Suns weigh?:
https://2.bp.blogspot.com/-wg62WBQ-7Rw/VjnCcGhJ_xI/AAAAAAAAC50/MNNR9XYTI_o/s1600-Ic42/009.jpg
since they're still undergoing fusion they'd weigh a decent amount no?
His arm wrestle with Samson and Atlas appears to shake the crescent shaped island they were on:
https://2.bp.blogspot.com/-OYw12MfcdaQ/VjnDNpPNvBI/AAAAAAAAC9A/G49w07VTtgs/s1600-Ic42/018.jpg
https://2.bp.blogspot.com/-gNYy2PEmV4Q/VjnDN3pfo5I/AAAAAAAAC9A/FWaZBM0Auhk/s1600-Ic42/019.jpg
Not that impressive but a neat feat either way, the movie version was way better tho:
https://www.youtube.com/watch?v=A8pNRyIlJ_g
Some will suggest him breaking Atlas's arm give him planetary strength but that's unquantified, Atlas has no feats to put him on that level.
I don't know how to quantify this to be honest:
https://2.bp.blogspot.com/-1HVrDq9KwbU/VjnD3ed0fkI/AAAAAAAADAM/rVSuFjW1vw4/s1600-Ic42/007.jpg
https://2.bp.blogspot.com/-cuSfH9LxXiY/VjnD3mo1xAI/AAAAAAAADAM/b3XyVvEaa5k/s1600-Ic42/009.jpg
Seems a bit hyperbolic and unspecified, but he's stated to be capable of cracking the Earth in two:
https://2.bp.blogspot.com/-f9Eujt8jZKo/VjnD5EhanzI/AAAAAAAADAM/JGG_Ft-jZvg/s1600-Ic42/014.jpg
Rams into a mountain with this much force:
https://2.bp.blogspot.com/-LD2OiI-EPM8/VjnF6_M1VRI/AAAAAAAADJ0/DxSjzeuHZQc/s1600-Ic42/018.jpg
This is the one I was talking about, Bar El and Lilo chuck Clark into the moon with enough force to crack the surface in half:
https://2.bp.blogspot.com/-Ib53eRp4hCQ/VjnHJQ6p6qI/AAAAAAAADQY/QxUd9UjpAm4/s1600-Ic42/011.jpg
https://2.bp.blogspot.com/-q6lj2eacjlE/VjnHJk-KNCI/AAAAAAAADQY/gp5NJAEqh6k/s1600-Ic42/012.jpg
Its not shown whether or not the entire surface was cracked or just the front half, and the crack itself obviously wasn't that big considering it could be helled together by a couple of bridges:
https://2.bp.blogspot.com/--RS4LDQiv58/VjnHJvfPKBI/AAAAAAAADQY/DIOsqv0QuBU/s1600-Ic42/013.jpg
But a good continental feat either way.
The big one, Superman completely cures the Sun with his own internal energy:
https://2.bp.blogspot.com/-DCoY6ReMlUE/VjnJHjnfLsI/AAAAAAAADas/kON90_QR_4A/s1600-Ic42/019.jpg
However, I don't think this can be quantified towards his striking power considering this is his total internal energy at work. I'll leave that for you to decide.
Of course he also flies from Earth the the Sun in a few moments, another good FTL feat at play.
Still can't find Morrison's quote on Superman "Juggling Stars," anyone want to post a link for that feel free.
Anyway Qaw I'll leave it to you to make a rating and pick up on anything I've missed.
200 quintillion tons is actually 3% of the Earth's mass and 2.5x the mass of the moon. He managed to extend his arm with that weight, I've done the calculations and under normal Earth gravity that woul equate to Large Country levels of potential energy. All of his feats are Post-Amp btw. 8 times gravity just means he can carry 8 times his own weight pretty easily. He flew to Alpha Centauri and back in the time it took Lois to shower, women take 10 minutes to shower. If you calculate the speed and therefore kinetic energy it's roughly moon busting I believe. Cracking the Earth in half takes 1/3 of the GBE, should scale to small planetary and his speed can be worked out from there as well. You could say the same for the moon. The miniature suns seem like scaled down versions of the our a main sequence star with relative density. That mountain one is obviously at least mountain busting.